diff --git a/backend/app/api/tags.py b/backend/app/api/tags.py
index 6751975..3ab53a9 100644
--- a/backend/app/api/tags.py
+++ b/backend/app/api/tags.py
@@ -415,15 +415,26 @@ async def series_remove(tag_id: int):
     return jsonify({"removed_count": n})
 
 
-@tags_bp.route("/series/<int:tag_id>/reorder", methods=["POST"])
-async def series_reorder(tag_id: int):
-    body = await request.get_json()
-    ids, err = _parse_bulk_ids(body, max_ids=500)
-    if err:
-        return err
+@tags_bp.route("/series/<int:tag_id>/pages/number", methods=["POST"])
+async def series_set_page_number(tag_id: int):
+    """Set one placed page's number — the operator's value (sparse, gaps
+    allowed); pass page_number: null to leave it unnumbered."""
+    body = await request.get_json() or {}
+    image_id, ierr = _opt_int(body, "image_id")
+    if ierr:
+        return ierr
+    if image_id is None:
+        return jsonify({"error": "image_id required"}), 400
+    if "page_number" not in body:
+        return jsonify({"error": "page_number required (may be null)"}), 400
+    page_number, perr = _opt_int(body, "page_number")
+    if perr:
+        return perr
     async with get_session() as session:
         try:
-            await SeriesService(session).reorder(tag_id, ids)
+            await SeriesService(session).set_page_number(
+                tag_id, image_id, page_number
+            )
         except SeriesError as exc:
             return _series_err(exc)
         await session.commit()
@@ -450,8 +461,9 @@ async def series_cover(tag_id: int):
 
 # ---- chapter dividers (FC-6.x) -------------------------------------------
 # A chapter is a cosmetic divider anchored to the page that begins it; it owns
-# no pages. Page ordering is series-wide (the /reorder endpoint above), so there
-# is no per-chapter reorder/merge/chapter-reorder — those are gone.
+# no pages. Page ordering follows each page's operator-set number (the
+# /pages/number endpoint), so there is no per-chapter reorder/merge — those are
+# gone.
 
 
 @tags_bp.route("/series/<int:tag_id>/chapters", methods=["POST"])
@@ -585,19 +597,19 @@ async def series_add_post(tag_id: int):
 
 @tags_bp.route("/series/<int:tag_id>/pending/place", methods=["POST"])
 async def series_place_pending(tag_id: int):
-    """Move staged (pending) pages into the placed run — before `before_image_id`
-    (a placed page) or appended when omitted (#789 P2)."""
+    """Place staged (pending) pages into the run, numbered sequentially from
+    `start_page` in the given order (#789). start_page null → unnumbered."""
     body = await request.get_json()
     ids, err = _parse_bulk_ids(body, max_ids=500)
     if err:
         return err
-    before, berr = _opt_int(body, "before_image_id")
-    if berr:
-        return berr
+    start, serr = _opt_int(body, "start_page")
+    if serr:
+        return serr
     async with get_session() as session:
         try:
             n = await SeriesService(session).place_pending(
-                tag_id, ids, before_image_id=before
+                tag_id, ids, start_page=start
             )
         except SeriesError as exc:
             return _series_err(exc)
diff --git a/backend/app/services/series_service.py b/backend/app/services/series_service.py
index f07bc9b..2bcbc32 100644
--- a/backend/app/services/series_service.py
+++ b/backend/app/services/series_service.py
@@ -11,7 +11,7 @@ nearest preceding divider. An image lives in at most one series
 All mutations are Core/set-based and run in the request transaction.
 """
 
-from sqlalchemy import and_, func, select, text, update
+from sqlalchemy import and_, func, select, update
 from sqlalchemy.dialects.postgresql import insert as pg_insert
 from sqlalchemy.exc import IntegrityError
 from sqlalchemy.ext.asyncio import AsyncSession
@@ -69,7 +69,10 @@ class SeriesService:
                         SeriesPage.status == "placed",
                     )
                 )
-                .order_by(SeriesPage.page_number.asc(), SeriesPage.id.asc())
+                .order_by(
+                    SeriesPage.page_number.asc().nulls_last(),
+                    SeriesPage.id.asc(),
+                )
             )
         ).scalars().all()
         return list(rows)
@@ -88,25 +91,6 @@ class SeriesService:
             raise SeriesError(f"image {image_id} is not in this series")
         return pid
 
-    async def _renumber(self, series_tag_id: int) -> None:
-        """Compact page_number to 1..N preserving current order (set-based)."""
-        await self.session.execute(
-            text(
-                """
-                WITH ordered AS (
-                    SELECT id, ROW_NUMBER() OVER (
-                        ORDER BY page_number, id
-                    ) AS rn
-                    FROM series_page WHERE series_tag_id = :sid
-                )
-                UPDATE series_page sp SET page_number = ordered.rn
-                FROM ordered
-                WHERE sp.id = ordered.id AND sp.page_number <> ordered.rn
-                """
-            ),
-            {"sid": series_tag_id},
-        )
-
     async def _require_divider(self, series_tag_id: int, divider_id: int):
         row = (
             await self.session.execute(
@@ -148,6 +132,30 @@ class SeriesService:
             prev = d
         return out
 
+    @staticmethod
+    def _page_gaps(pages: list[dict]) -> list[dict]:
+        """Missing-number gaps between consecutive NUMBERED placed pages — one
+        entry per gap (e.g. pages 2 then 5 → one gap 3–4). The UI renders each as
+        a single block whose edges accept a dropped page. Unnumbered pages (at
+        the tail) don't participate."""
+        out: list[dict] = []
+        prev = None
+        for p in pages:
+            n = p["page_number"]
+            if n is None:
+                continue
+            if prev is not None and n > prev["page_number"] + 1:
+                out.append(
+                    {
+                        "after_image_id": prev["image_id"],
+                        "before_image_id": p["image_id"],
+                        "from": prev["page_number"] + 1,
+                        "to": n - 1,
+                    }
+                )
+            prev = p
+        return out
+
     async def list_pages(self, series_tag_id: int) -> dict:
         tag = await self._require_series(series_tag_id)
         rows = (
@@ -172,7 +180,10 @@ class SeriesService:
                         SeriesPage.status == "placed",
                     )
                 )
-                .order_by(SeriesPage.page_number.asc(), SeriesPage.id.asc())
+                .order_by(
+                    SeriesPage.page_number.asc().nulls_last(),
+                    SeriesPage.id.asc(),
+                )
             )
         ).all()
         pages = [
@@ -259,6 +270,7 @@ class SeriesService:
                         if r.primary_post_id is not None
                         else None
                     ),
+                    "start_page": None,
                     "pages": [],
                 }
                 by_post[r.primary_post_id] = grp
@@ -273,10 +285,18 @@ class SeriesService:
                     "image_url": f"/images/{r.path.split('/images/', 1)[-1]}",
                 }
             )
+            # Group start page = the post's parsed starting page (stored on the
+            # staged pages); surfaced as the default for "Place from page N".
+            if r.stated_page is not None:
+                cur = grp["start_page"]
+                grp["start_page"] = (
+                    r.stated_page if cur is None else min(cur, r.stated_page)
+                )
 
         return {
             "series": {"id": tag.id, "name": tag.name},
             "pages": pages,
+            "gaps": self._page_gaps(pages),
             "dividers": dividers,
             "pending": pending_groups,
             "part_gaps": self._part_gaps(dividers),
@@ -357,45 +377,58 @@ class SeriesService:
             )
         )
         # Dividers anchored to a removed page cascade away (chapter merges into
-        # the preceding run); compact the remaining pages back to 1..N.
-        await self._renumber(series_tag_id)
+        # the preceding run). Page numbers are operator-set and sparse, so we do
+        # NOT renumber — removing a page just leaves a gap.
         return res.rowcount or 0
 
-    async def reorder(
-        self, series_tag_id: int, ordered_image_ids: list[int]
+    async def set_page_number(
+        self, series_tag_id: int, image_id: int, page_number: int | None
     ) -> None:
-        """Series-wide reorder. ordered_image_ids must be exactly the series'
-        pages; page_number is rewritten 1..N in that order."""
+        """Set one placed page's number — the operator's value: sparse, gaps
+        allowed, or None to leave it unnumbered (sorts to the end). No other page
+        is touched; reading order follows the numbers."""
         await self._require_series(series_tag_id)
-        ordered = self._clean_ids(ordered_image_ids)
-        current = set(await self._page_order(series_tag_id))
-        if set(ordered) != current or len(ordered) != len(current):
-            raise SeriesError(
-                "ordered image_ids must exactly match the series' pages"
-            )
-        for idx, iid in enumerate(ordered, start=1):
-            await self.session.execute(
-                update(SeriesPage)
-                .where(
-                    and_(
-                        SeriesPage.series_tag_id == series_tag_id,
-                        SeriesPage.image_id == iid,
-                    )
+        res = await self.session.execute(
+            update(SeriesPage)
+            .where(
+                and_(
+                    SeriesPage.series_tag_id == series_tag_id,
+                    SeriesPage.image_id == image_id,
+                    SeriesPage.status == "placed",
                 )
-                .values(page_number=idx)
+            )
+            .values(page_number=page_number)
+        )
+        if (res.rowcount or 0) == 0:
+            raise SeriesError(
+                f"image {image_id} is not a placed page of this series"
             )
 
     async def set_cover(self, series_tag_id: int, image_id: int) -> None:
-        """Cover = the first page. Move the image to the front of the series."""
+        """Cover = the lowest-numbered page. Renumber the chosen image to sit
+        just before the current minimum so it sorts first."""
         await self._require_series(series_tag_id)
-        pages = await self._page_order(series_tag_id)
-        if image_id not in pages:
-            raise SeriesError(f"image {image_id} is not in this series")
-        if pages and pages[0] != image_id:
-            await self.reorder(
-                series_tag_id,
-                [image_id] + [p for p in pages if p != image_id],
+        await self._page_id_for(series_tag_id, image_id)  # membership guard
+        min_other = await self.session.scalar(
+            select(func.min(SeriesPage.page_number)).where(
+                and_(
+                    SeriesPage.series_tag_id == series_tag_id,
+                    SeriesPage.status == "placed",
+                    SeriesPage.image_id != image_id,
+                )
             )
+        )
+        new_pn = (min_other - 1) if min_other is not None else 1
+        await self.session.execute(
+            update(SeriesPage)
+            .where(
+                and_(
+                    SeriesPage.series_tag_id == series_tag_id,
+                    SeriesPage.image_id == image_id,
+                )
+            )
+            .values(page_number=new_pn)
+        )
 
     # ---- chapter dividers -------------------------------------------------
 
@@ -561,8 +594,10 @@ class SeriesService:
                 SeriesPage.image_id.in_(to_stage)
             )
         )
+        # Store the post's parsed START page on every staged page (constant), so
+        # the group's start survives junk removal and seeds "Place from page N".
         rng = parse_page_range(f"{post.post_title or ''} {post.description or ''}")
-        sp = self._stated_map(image_ids, rng[0] if rng else None) or {}
+        start = rng[0] if rng else None
         await self.session.execute(
             pg_insert(SeriesPage).values(
                 [
@@ -571,7 +606,7 @@ class SeriesService:
                         "image_id": iid,
                         "status": "pending",
                         "page_number": None,
-                        "stated_page": sp.get(iid),
+                        "stated_page": start,
                     }
                     for iid in to_stage
                 ]
@@ -583,11 +618,13 @@ class SeriesService:
         self,
         series_tag_id: int,
         image_ids: list[int],
-        before_image_id: int | None = None,
+        start_page: int | None = None,
     ) -> int:
-        """Move staged (pending) pages into the placed run — spliced in just
-        before `before_image_id` (a placed page), or appended at the end when
-        it's None. Page numbers are then rewritten 1..N across the run."""
+        """Place staged (pending) pages into the run, numbering them sequentially
+        from `start_page` in the given order (start_page, start_page+1, …). With
+        start_page None they're placed unnumbered (sorting to the tail). Drop the
+        junk BEFORE placing so the numbers line up; only pending pages are
+        touched, and other pages keep their numbers."""
         await self._require_series(series_tag_id)
         ids = self._clean_ids(image_ids)
         rows = dict(
@@ -602,32 +639,11 @@ class SeriesService:
                 )
             ).all()
         )
+        # Preserve the caller's order, restricted to actually-pending pages.
         staged = [i for i in ids if rows.get(i) == "pending"]
         if not staged:
             return 0
-        placed = await self._page_order(series_tag_id)
-        if before_image_id is not None and before_image_id not in placed:
-            raise SeriesError(
-                "before_image_id is not a placed page of this series"
-            )
-        new_order: list[int] = []
-        for iid in placed:
-            if iid == before_image_id:
-                new_order.extend(staged)
-            new_order.append(iid)
-        if before_image_id is None:
-            new_order.extend(staged)
-        await self.session.execute(
-            update(SeriesPage)
-            .where(
-                and_(
-                    SeriesPage.series_tag_id == series_tag_id,
-                    SeriesPage.image_id.in_(staged),
-                )
-            )
-            .values(status="placed")
-        )
-        for idx, iid in enumerate(new_order, start=1):
+        for offset, iid in enumerate(staged):
             await self.session.execute(
                 update(SeriesPage)
                 .where(
@@ -636,7 +652,12 @@ class SeriesService:
                         SeriesPage.image_id == iid,
                     )
                 )
-                .values(page_number=idx)
+                .values(
+                    status="placed",
+                    page_number=(
+                        start_page + offset if start_page is not None else None
+                    ),
+                )
             )
         return len(staged)
 
diff --git a/frontend/src/stores/seriesManage.js b/frontend/src/stores/seriesManage.js
index 47f22e3..2cfa5cf 100644
--- a/frontend/src/stores/seriesManage.js
+++ b/frontend/src/stores/seriesManage.js
@@ -20,7 +20,8 @@ export const useSeriesManageStore = defineStore('seriesManage', () => {
   const series = ref(null)
   const pages = ref([])              // flat, ordered: [{image_id, page_number, stated_page, thumbnail_url, image_url, source_post}]
   const dividers = ref([])           // [{id, anchor_image_id, page_number, title, stated_part}]
-  const pending = ref([])            // staged-from-post: [{post:{id,title}|null, pages:[{image_id, stated_page, thumbnail_url, image_url}]}]
+  const gaps = ref([])               // missing-number gaps: [{after_image_id, before_image_id, from, to}]
+  const pending = ref([])            // staged-from-post: [{post:{id,title}|null, start_page, pages:[{image_id, stated_page, thumbnail_url, image_url}]}]
   const partGaps = ref([])           // [{after_divider_id, start, end}]
   const pageCount = ref(0)
   const picker = ref([])             // gallery scroll results
@@ -36,6 +37,7 @@ export const useSeriesManageStore = defineStore('seriesManage', () => {
       series.value = body.series
       pages.value = body.pages || []
       dividers.value = body.dividers || []
+      gaps.value = body.gaps || []
       pending.value = body.pending || []
       partGaps.value = body.part_gaps || []
       pageCount.value = pages.value.length
@@ -57,14 +59,19 @@ export const useSeriesManageStore = defineStore('seriesManage', () => {
     return partGaps.value.find(g => g.after_divider_id === dividerId) || null
   }
 
-  // ---- pages (series-wide) ----
-  async function reorder(orderedImageIds) {
-    await api.post(`/api/series/${tagId.value}/reorder`, {
-      body: { image_ids: orderedImageIds }
+  // ---- pages (number-driven) ----
+  // Set one page's number (sparse, gaps allowed; pass null to unnumber).
+  async function setPageNumber(imageId, pageNumber) {
+    await api.post(`/api/series/${tagId.value}/pages/number`, {
+      body: { image_id: imageId, page_number: pageNumber }
     })
     await refresh()
   }
 
+  function gapAfter(imageId) {
+    return gaps.value.find(g => g.after_image_id === imageId) || null
+  }
+
   async function remove(imageId) {
     await api.post(`/api/series/${tagId.value}/pages/remove`, {
       body: { image_ids: [imageId] }
@@ -108,9 +115,10 @@ export const useSeriesManageStore = defineStore('seriesManage', () => {
   }
 
   // ---- pending staging (add-from-post) ----
-  async function placePending(imageIds, beforeImageId = null) {
+  // Place pending pages, numbered sequentially from startPage in the given order.
+  async function placePending(imageIds, startPage = null) {
     await api.post(`/api/series/${tagId.value}/pending/place`, {
-      body: { image_ids: imageIds, before_image_id: beforeImageId }
+      body: { image_ids: imageIds, start_page: startPage }
     })
     await refresh()
     toast({ text: 'Pages placed into the series', type: 'success' })
@@ -143,10 +151,10 @@ export const useSeriesManageStore = defineStore('seriesManage', () => {
   }
 
   return {
-    tagId, series, pages, dividers, pending, partGaps, pageCount,
+    tagId, series, pages, dividers, gaps, pending, partGaps, pageCount,
     picker, pickerCursor, pickerSelection, loading,
-    load, refresh, dividerAt, partGapAfter,
-    reorder, remove, setCover, placePending,
+    load, refresh, dividerAt, partGapAfter, gapAfter,
+    setPageNumber, remove, setCover, placePending,
     createDivider, renameDivider, setDividerPart, deleteDivider,
     loadPicker, togglePick, addSelected
   }
diff --git a/frontend/src/views/SeriesManageView.vue b/frontend/src/views/SeriesManageView.vue
index f16b43a..68746ec 100644
--- a/frontend/src/views/SeriesManageView.vue
+++ b/frontend/src/views/SeriesManageView.vue
@@ -25,23 +25,22 @@
     </div>
 
     <p class="fc-series__hint">
-      One continuous series. <strong>Drag any page</strong> to set its order —
-      the numbers are the page's place in the whole series. Use a page's
-      <strong>⋮ → Start a chapter here</strong> to drop a labeled divider before
-      it. New pages from <strong>Add pages</strong> append to the end, ready to
-      be dragged into place.
+      One continuous series. <strong>Each page's number is yours</strong> — type
+      it on the card; gaps are fine. Drag a page onto a <strong>gap's edge</strong>
+      to give it the adjacent number, or onto the end to append. New pages from a
+      post land in the <strong>pending tray</strong> to sort.
     </p>
 
-    <!-- Pending tray: pages staged from a post, grouped by source post, for the
-         operator to drop junk and place into the run. -->
+    <!-- Pending tray: pages staged from a post, grouped by source post. Drop the
+         junk, set the start page, then place them numbered from there. -->
     <div v-if="store.pending.length" class="fc-pending">
       <div class="fc-pending__head">
         <v-icon size="small">mdi-tray-arrow-down</v-icon>
         <span>Pending — sort into the series</span>
       </div>
       <p class="fc-pending__hint">
-        New pages from a post land here. Drop the ones that don't belong
-        (text-free alternates, bumpers), then place the rest into the run.
+        Drop the pages that don't belong (text-free alternates, bumpers), then
+        place the rest — they'll be numbered up from the start page you set.
       </p>
       <section v-for="(grp, gi) in store.pending" :key="gi" class="fc-pgroup">
         <header class="fc-pgroup__head">
@@ -50,22 +49,26 @@
             {{ grp.post?.title || 'Unknown post' }}
           </span>
           <span class="fc-pgroup__count">{{ grp.pages.length }} pending</span>
+          <label class="fc-pgroup__startfield">
+            from page
+            <input
+              class="fc-pgroup__start" type="number" min="1" placeholder="?"
+              :value="startDraft[gi] ?? grp.start_page ?? ''"
+              @input="startDraft[gi] = $event.target.value"
+            >
+          </label>
           <v-spacer />
           <v-btn
             size="small" variant="tonal" color="accent"
             prepend-icon="mdi-playlist-plus"
-            @click="store.placePending(grp.pages.map(p => p.image_id))"
-          >Place all into series</v-btn>
+            :disabled="effectiveStart(grp, gi) == null"
+            @click="placeGroup(grp, gi)"
+          >Place from page {{ effectiveStart(grp, gi) ?? '?' }}</v-btn>
         </header>
         <div class="fc-pgroup__pages">
           <div v-for="p in grp.pages" :key="p.image_id" class="fc-ppage">
             <img :src="p.thumbnail_url" alt="" loading="lazy" />
             <div class="fc-ppage__actions">
-              <v-btn
-                size="x-small" variant="flat" icon="mdi-playlist-plus"
-                title="Place this page into the series"
-                @click="store.placePending([p.image_id])"
-              />
               <v-btn
                 size="x-small" variant="flat" icon="mdi-close"
                 title="Drop — doesn't belong in the series"
@@ -77,66 +80,58 @@
       </section>
     </div>
 
-    <!-- One continuous page run; chapter dividers render inline before their
-         anchor page. -->
+    <!-- One continuous run, ordered by each page's number. Chapter dividers and
+         missing-number gap blocks render inline. -->
     <div v-if="store.pages.length" class="fc-run">
-      <template v-for="(p, pi) in store.pages" :key="p.image_id">
+      <template v-for="p in store.pages" :key="p.image_id">
         <!-- chapter divider bar, if one is anchored at this page -->
-        <template v-if="store.dividerAt(p.image_id)">
-          <div class="fc-divider">
-            <v-icon size="small" class="fc-divider__icon">mdi-format-section</v-icon>
-            <label class="fc-divider__partfield" title="Part number for this chapter">
-              <span class="fc-divider__partlabel">Part</span>
-              <input
-                class="fc-divider__partnum" type="number" min="1"
-                :value="partDraft[store.dividerAt(p.image_id).id] ?? ''"
-                placeholder="—"
-                @input="partDraft[store.dividerAt(p.image_id).id] = $event.target.value"
-                @keydown.enter.prevent="commitPart(store.dividerAt(p.image_id))"
-                @blur="commitPart(store.dividerAt(p.image_id))"
-              >
-            </label>
-            <v-text-field
-              :model-value="titleDraft[store.dividerAt(p.image_id).id]"
-              placeholder="Untitled chapter"
-              density="compact" variant="plain" hide-details
-              class="fc-divider__title"
-              @update:model-value="titleDraft[store.dividerAt(p.image_id).id] = $event"
-              @keydown.enter="commitTitle(store.dividerAt(p.image_id))"
-              @blur="commitTitle(store.dividerAt(p.image_id))"
-            />
-            <v-spacer />
-            <v-btn
-              size="x-small" variant="text" icon="mdi-close"
-              title="Remove this chapter divider"
-              @click="store.deleteDivider(store.dividerAt(p.image_id).id)"
-            />
-          </div>
-          <div
-            v-if="store.partGapAfter(store.dividerAt(p.image_id).id)"
-            class="fc-gap"
-          >
-            <v-icon size="x-small">mdi-alert-outline</v-icon>
-            Missing
-            <template v-if="gapText(p.image_id).single">
-              Part {{ gapText(p.image_id).start }}
-            </template>
-            <template v-else>
-              Parts {{ gapText(p.image_id).start }}–{{ gapText(p.image_id).end }}
-            </template>
-          </div>
-        </template>
+        <div v-if="store.dividerAt(p.image_id)" class="fc-divider">
+          <v-icon size="small" class="fc-divider__icon">mdi-format-section</v-icon>
+          <label class="fc-divider__partfield" title="Part number for this chapter">
+            <span class="fc-divider__partlabel">Part</span>
+            <input
+              class="fc-divider__partnum" type="number" min="1"
+              :value="partDraft[store.dividerAt(p.image_id).id] ?? ''"
+              placeholder="—"
+              @input="partDraft[store.dividerAt(p.image_id).id] = $event.target.value"
+              @keydown.enter.prevent="commitPart(store.dividerAt(p.image_id))"
+              @blur="commitPart(store.dividerAt(p.image_id))"
+            >
+          </label>
+          <v-text-field
+            :model-value="titleDraft[store.dividerAt(p.image_id).id]"
+            placeholder="Untitled chapter"
+            density="compact" variant="plain" hide-details
+            class="fc-divider__title"
+            @update:model-value="titleDraft[store.dividerAt(p.image_id).id] = $event"
+            @keydown.enter="commitTitle(store.dividerAt(p.image_id))"
+            @blur="commitTitle(store.dividerAt(p.image_id))"
+          />
+          <v-spacer />
+          <v-btn
+            size="x-small" variant="text" icon="mdi-close"
+            title="Remove this chapter divider"
+            @click="store.deleteDivider(store.dividerAt(p.image_id).id)"
+          />
+        </div>
 
         <!-- the page -->
         <div
           class="fc-page" draggable="true"
-          :class="{ 'fc-page--dragging': drag === pi }"
-          @dragstart="drag = pi"
+          :class="{ 'fc-page--dragging': drag === p.image_id }"
+          @dragstart="drag = p.image_id"
           @dragend="drag = null"
-          @dragover.prevent
-          @drop="onDrop(pi)"
         >
-          <span class="fc-page__pn">{{ p.page_number }}</span>
+          <label class="fc-page__numfield" title="Page number (gaps allowed)">
+            <input
+              class="fc-page__num" type="number" min="1"
+              :value="numDraft[p.image_id] ?? ''" placeholder="—"
+              @input="numDraft[p.image_id] = $event.target.value"
+              @keydown.enter.prevent="commitNum(p)"
+              @blur="commitNum(p)"
+              @mousedown.stop
+            >
+          </label>
           <img :src="p.thumbnail_url" alt="" loading="lazy" />
           <span
             v-if="p.source_post?.title" class="fc-page__src"
@@ -161,7 +156,29 @@
             />
           </div>
         </div>
+
+        <!-- gap block after this page (drop a page on an edge to number it) -->
+        <div
+          v-if="store.gapAfter(p.image_id)" class="fc-gapblock"
+          @dragover.prevent
+        >
+          <div
+            class="fc-gapblock__edge"
+            @drop="onGapDrop(store.gapAfter(p.image_id).from)"
+          >← {{ store.gapAfter(p.image_id).from }}</div>
+          <span class="fc-gapblock__label">{{ gapLabel(store.gapAfter(p.image_id)) }}</span>
+          <div
+            class="fc-gapblock__edge"
+            @drop="onGapDrop(store.gapAfter(p.image_id).to)"
+          >{{ store.gapAfter(p.image_id).to }} →</div>
+        </div>
       </template>
+
+      <!-- append zone: drop here to give the page the next number -->
+      <div class="fc-append" @dragover.prevent @drop="onAppendDrop">
+        <v-icon size="small">mdi-tray-plus</v-icon>
+        drop here to append (page {{ nextNumber }})
+      </div>
     </div>
 
     <div v-else class="fc-series__empty">
@@ -217,30 +234,37 @@
 </template>
 
 <script setup>
-import { onMounted, reactive, ref, watch } from 'vue'
+import { computed, onMounted, reactive, ref, watch } from 'vue'
 import { useRoute } from 'vue-router'
-import { useSeriesManageStore, moveItem } from '../stores/seriesManage.js'
+import { useSeriesManageStore } from '../stores/seriesManage.js'
 import { useInfiniteScroll } from '../composables/useInfiniteScroll.js'
 import TagRenameDialog from '../components/modal/TagRenameDialog.vue'
 
 const route = useRoute()
 const store = useSeriesManageStore()
 const sentinel = ref(null)
-const drag = ref(null)            // index in the flat pages run being dragged
+const drag = ref(null)            // image_id of the page being dragged
+const numDraft = reactive({})     // image_id -> draft page number (string)
 const titleDraft = reactive({})   // dividerId -> draft title
 const partDraft = reactive({})    // dividerId -> draft stated_part (string)
+const startDraft = reactive({})   // pending group index -> draft start page (string)
 const pickerOpen = ref(false)
 const renameOpen = ref(false)
 
-// A series IS a Tag(kind=series); TagRenameDialog PATCHes /api/tags/<id> and
-// handles the same-name collision→merge flow. Reflect the new name in place.
 function onRenamed(updated) {
   renameOpen.value = false
   if (store.series && updated?.name) store.series.name = updated.name
 }
 
-// Keep local divider drafts in sync with loaded dividers; edits commit on
-// blur/Enter, which refreshes and resets the draft to the saved value.
+// Keep card/divider drafts in sync with loaded data; edits commit on blur/Enter,
+// which refreshes and resets the draft to the saved value.
+watch(() => store.pages, (ps) => {
+  for (const k of Object.keys(numDraft)) delete numDraft[k]
+  for (const p of ps) {
+    numDraft[p.image_id] = p.page_number == null ? '' : String(p.page_number)
+  }
+}, { immediate: true })
+
 watch(() => store.dividers, (divs) => {
   for (const k of Object.keys(titleDraft)) delete titleDraft[k]
   for (const k of Object.keys(partDraft)) delete partDraft[k]
@@ -250,6 +274,46 @@ watch(() => store.dividers, (divs) => {
   }
 }, { immediate: true })
 
+// Next number = one past the highest assigned page number (1 if none).
+const nextNumber = computed(() => {
+  let max = 0
+  for (const p of store.pages) {
+    if (p.page_number != null && p.page_number > max) max = p.page_number
+  }
+  return max + 1
+})
+
+function commitNum(p) {
+  const raw = (numDraft[p.image_id] ?? '').trim()
+  const next = raw === '' ? null : parseInt(raw, 10)
+  if (raw !== '' && (Number.isNaN(next) || next < 1)) {
+    numDraft[p.image_id] = p.page_number == null ? '' : String(p.page_number)
+    return
+  }
+  if (next === (p.page_number ?? null)) return
+  store.setPageNumber(p.image_id, next)
+}
+
+function onGapDrop(number) {
+  if (drag.value == null) return
+  const id = drag.value
+  drag.value = null
+  store.setPageNumber(id, number)
+}
+
+function onAppendDrop() {
+  if (drag.value == null) return
+  const id = drag.value
+  drag.value = null
+  store.setPageNumber(id, nextNumber.value)
+}
+
+function gapLabel(g) {
+  return g.from === g.to
+    ? `page ${g.from} missing`
+    : `pages ${g.from}–${g.to} missing`
+}
+
 function commitTitle(d) {
   const v = (titleDraft[d.id] || '').trim()
   if (v === (d.title || '')) return
@@ -267,19 +331,21 @@ function commitPart(d) {
   store.setDividerPart(d.id, next)
 }
 
-function gapText(anchorImageId) {
-  const d = store.dividerAt(anchorImageId)
-  const g = d ? store.partGapAfter(d.id) : null
-  return { start: g?.start, end: g?.end, single: g && g.start === g.end }
+// Pending: effective start page = the typed override, else the post's parsed
+// start. null when neither is set (operator must type one).
+function effectiveStart(grp, gi) {
+  const raw = (startDraft[gi] ?? '').toString().trim()
+  if (raw !== '') {
+    const n = parseInt(raw, 10)
+    return Number.isNaN(n) || n < 1 ? null : n
+  }
+  return grp.start_page ?? null
 }
 
-function onDrop(toIdx) {
-  if (drag.value === null || drag.value === toIdx) { drag.value = null; return }
-  const ordered = moveItem(
-    store.pages.map(p => p.image_id), drag.value, toIdx
-  )
-  drag.value = null
-  store.reorder(ordered)
+function placeGroup(grp, gi) {
+  const start = effectiveStart(grp, gi)
+  if (start == null) return
+  store.placePending(grp.pages.map(p => p.image_id), start)
 }
 
 useInfiniteScroll(sentinel, () => store.loadPicker())
@@ -303,7 +369,7 @@ onMounted(async () => {
   margin-bottom: 18px; max-width: 820px;
 }
 
-/* One continuous page run with inline divider bars. */
+/* One continuous run with inline dividers + gap blocks. */
 .fc-run {
   display: grid; gap: 10px; max-width: 1100px;
   grid-template-columns: repeat(auto-fill, minmax(150px, 1fr));
@@ -339,7 +405,38 @@ onMounted(async () => {
 }
 .fc-divider__title { flex: 1 1 200px; min-width: 120px; font-size: 15px; }
 
-/* Big page tiles */
+/* Gap block — one per gap; drop a page on an edge to number it. */
+.fc-gapblock {
+  grid-column: 1 / -1;
+  display: flex; align-items: stretch; gap: 8px;
+  padding: 4px; border: 1px dashed rgb(var(--v-theme-on-surface-variant), 0.5);
+  border-radius: 8px;
+}
+.fc-gapblock__edge {
+  display: flex; align-items: center; justify-content: center;
+  min-width: 80px; padding: 6px 10px; border-radius: 6px;
+  font-variant-numeric: tabular-nums; font-size: 13px;
+  background: rgb(var(--v-theme-surface-light));
+  color: rgb(var(--v-theme-on-surface-variant)); cursor: copy;
+}
+.fc-gapblock__edge:hover {
+  background: rgb(var(--v-theme-accent), 0.2);
+  color: rgb(var(--v-theme-accent));
+}
+.fc-gapblock__label {
+  flex: 1; display: flex; align-items: center; justify-content: center;
+  font-size: 12px; color: rgb(var(--v-theme-on-surface-variant));
+}
+
+.fc-append {
+  grid-column: 1 / -1;
+  display: flex; align-items: center; justify-content: center; gap: 8px;
+  padding: 12px; border: 1px dashed rgb(var(--v-theme-on-surface-variant), 0.4);
+  border-radius: 8px; font-size: 13px;
+  color: rgb(var(--v-theme-on-surface-variant));
+}
+
+/* Page tiles */
 .fc-page {
   position: relative; border-radius: 8px; overflow: hidden; cursor: grab;
   background: rgb(var(--v-theme-surface-light));
@@ -350,13 +447,19 @@ onMounted(async () => {
   width: 100%; aspect-ratio: 3 / 4; object-fit: contain;
   display: block; background: rgb(var(--v-theme-background));
 }
-.fc-page__pn {
+.fc-page__numfield {
   position: absolute; top: 6px; left: 6px; z-index: 2;
-  min-width: 24px; height: 24px; padding: 0 6px; border-radius: 12px;
-  display: inline-flex; align-items: center; justify-content: center;
-  font-size: 13px; font-weight: 600; font-variant-numeric: tabular-nums;
-  background: rgb(var(--v-theme-accent)); color: rgb(var(--v-theme-on-accent, 0 0 0));
+  background: rgb(var(--v-theme-accent)); border-radius: 12px;
+  padding: 0 4px; height: 24px; display: flex; align-items: center;
 }
+.fc-page__num {
+  width: 34px; height: 22px; text-align: center;
+  font-size: 13px; font-weight: 600; font-variant-numeric: tabular-nums;
+  background: transparent; border: none;
+  color: rgb(var(--v-theme-on-accent, 0 0 0));
+}
+.fc-page__num:focus { outline: none; }
+.fc-page__num::placeholder { color: rgb(var(--v-theme-on-accent, 0 0 0)); opacity: 0.5; }
 .fc-page__src {
   position: absolute; bottom: 0; left: 0; right: 0; z-index: 2;
   display: flex; align-items: center; gap: 4px; padding: 3px 6px;
@@ -372,11 +475,6 @@ onMounted(async () => {
   background: rgba(0, 0, 0, 0.55); color: #fff;
 }
 
-.fc-gap {
-  grid-column: 1 / -1;
-  display: flex; align-items: center; gap: 6px; padding: 2px 10px;
-  font-size: 12px; color: rgb(var(--v-theme-warning, var(--v-theme-accent)));
-}
 .fc-series__empty {
   padding: 40px; text-align: center; color: rgb(var(--v-theme-on-surface-variant));
   max-width: 1100px;
@@ -401,15 +499,27 @@ onMounted(async () => {
 .fc-pgroup { margin-bottom: 12px; }
 .fc-pgroup__head {
   display: flex; align-items: center; gap: 10px; margin-bottom: 6px;
+  flex-wrap: wrap;
 }
 .fc-pgroup__title {
-  display: inline-flex; align-items: center; gap: 4px; max-width: 360px;
+  display: inline-flex; align-items: center; gap: 4px; max-width: 320px;
   overflow: hidden; text-overflow: ellipsis; white-space: nowrap;
   font-size: 13px; font-weight: 600;
 }
 .fc-pgroup__count {
   font-size: 12px; color: rgb(var(--v-theme-on-surface-variant));
 }
+.fc-pgroup__startfield {
+  display: inline-flex; align-items: center; gap: 4px;
+  font-size: 12px; color: rgb(var(--v-theme-on-surface-variant));
+}
+.fc-pgroup__start {
+  width: 56px; text-align: center; font-size: 13px;
+  background: rgb(var(--v-theme-surface-light));
+  border: 1px solid transparent; border-radius: 4px; padding: 2px 4px;
+  color: rgb(var(--v-theme-on-surface));
+}
+.fc-pgroup__start:focus { outline: none; border-color: rgb(var(--v-theme-accent)); }
 .fc-pgroup__pages {
   display: grid; gap: 8px;
   grid-template-columns: repeat(auto-fill, minmax(110px, 1fr));
diff --git a/frontend/test/seriesManage.spec.js b/frontend/test/seriesManage.spec.js
index e251430..8a19744 100644
--- a/frontend/test/seriesManage.spec.js
+++ b/frontend/test/seriesManage.spec.js
@@ -42,19 +42,30 @@ describe('seriesManage', () => {
     expect(s.pageCount).toBe(1)
   })
 
-  it('reorder posts ordered ids to the series reorder route', async () => {
+  it('setPageNumber posts the image + number to /pages/number', async () => {
     const s = useSeriesManageStore()
     s.tagId = 7
     const calls = []
     stubFetch((url, init) => {
       calls.push({ url, body: init.body ? JSON.parse(init.body) : null })
-      if (url.includes('/reorder')) return { status: 200, body: { ok: true } }
+      if (url.includes('/pages/number')) return { status: 200, body: { ok: true } }
       return { status: 200, body: SERIES_BODY }
     })
-    await s.reorder([30, 10, 20])
-    const r = calls.find(c => c.url.includes('/reorder'))
-    expect(r.url).toContain('/api/series/7/reorder')
-    expect(r.body).toEqual({ image_ids: [30, 10, 20] })
+    await s.setPageNumber(42, 5)
+    const r = calls.find(c => c.url.includes('/pages/number'))
+    expect(r.url).toContain('/api/series/7/pages/number')
+    expect(r.body).toEqual({ image_id: 42, page_number: 5 })
+  })
+
+  it('gapAfter looks up a gap by its after_image_id', async () => {
+    const s = useSeriesManageStore()
+    stubFetch(() => ({
+      status: 200,
+      body: { ...SERIES_BODY, gaps: [{ after_image_id: 1, before_image_id: 9, from: 2, to: 3 }] }
+    }))
+    await s.load(7)
+    expect(s.gapAfter(1)).toEqual({ after_image_id: 1, before_image_id: 9, from: 2, to: 3 })
+    expect(s.gapAfter(99)).toBeNull()
   })
 
   it('createDivider posts the anchor image + labels', async () => {
diff --git a/tests/test_api_series.py b/tests/test_api_series.py
index 0ac39fa..8f11be9 100644
--- a/tests/test_api_series.py
+++ b/tests/test_api_series.py
@@ -44,10 +44,10 @@ async def test_add_over_cap_400(client):
 
 
 @pytest.mark.asyncio
-async def test_reorder_mismatch_400(client):
-    sid = await _series(client, "Re")
+async def test_set_page_number_requires_image_id(client):
+    sid = await _series(client, "Num")
     resp = await client.post(
-        f"/api/series/{sid}/reorder", json={"image_ids": [1, 2, 3]}
+        f"/api/series/{sid}/pages/number", json={"page_number": 5}
     )
     assert resp.status_code == 400
 
diff --git a/tests/test_series_pending.py b/tests/test_series_pending.py
index dbab5b4..ed65c96 100644
--- a/tests/test_series_pending.py
+++ b/tests/test_series_pending.py
@@ -76,25 +76,29 @@ async def test_place_pending_appends_and_flips_status(db):
     imgs = await _post_images(db, post, artist, 3)
     await svc.add_post(sid, post.id)
 
-    placed = await svc.place_pending(sid, imgs)
+    placed = await svc.place_pending(sid, imgs, start_page=3)
     assert placed == 3
     assert await _placed_order(db, sid) == seed + imgs
-    # nothing left pending; page numbers compact 1..5
+    # nothing left pending; the placed pages are numbered 1,2 (seed) + 3,4,5
     data = await svc.list_pages(sid)
     assert data["pending"] == []
     assert [p["page_number"] for p in data["pages"]] == [1, 2, 3, 4, 5]
 
 
 @pytest.mark.asyncio
-async def test_place_pending_before_a_placed_page(db):
-    svc, artist, sid, seed = await _setup(db, "PB")
-    a, b = seed
+async def test_place_pending_numbers_from_start(db):
+    svc, artist, sid, seed = await _setup(db, "PB")  # seed numbered 1, 2
     post = await _post(db, artist, "PB pages", "pb-p")
     x, y = await _post_images(db, post, artist, 2)
     await svc.add_post(sid, post.id)
 
-    await svc.place_pending(sid, [x, y], before_image_id=b)
-    assert await _placed_order(db, sid) == [a, x, y, b]
+    await svc.place_pending(sid, [x, y], start_page=10)
+    data = await svc.list_pages(sid)
+    nums = {p["image_id"]: p["page_number"] for p in data["pages"]}
+    assert nums[x] == 10
+    assert nums[y] == 11
+    # order = seed (1, 2) then x (10), y (11)
+    assert [p["image_id"] for p in data["pages"]] == seed + [x, y]
 
 
 @pytest.mark.asyncio
diff --git a/tests/test_series_service.py b/tests/test_series_service.py
index 00847b1..5d9fb38 100644
--- a/tests/test_series_service.py
+++ b/tests/test_series_service.py
@@ -84,17 +84,24 @@ async def test_remove(db):
 
 
 @pytest.mark.asyncio
-async def test_reorder_rewrites_and_rejects_mismatch(db):
+async def test_set_page_number_sparse_with_gaps(db):
     s = await TagService(db).find_or_create("S4", TagKind.series)
     i1, i2, i3 = await _img(db), await _img(db), await _img(db)
     svc = SeriesService(db)
-    await svc.add_images(s.id, [i1, i2, i3])
-    await svc.reorder(s.id, [i3, i1, i2])
-    assert await _order(db, s.id) == [i3, i1, i2]
+    await svc.add_images(s.id, [i1, i2, i3])   # numbered 1, 2, 3
+    # set a sparse number, leaving a gap
+    await svc.set_page_number(s.id, i3, 5)
+    out = await svc.list_pages(s.id)
+    assert [p["page_number"] for p in out["pages"]] == [1, 2, 5]
+    assert len(out["gaps"]) == 1
+    assert out["gaps"][0]["from"] == 3
+    assert out["gaps"][0]["to"] == 4
+    # unnumber a page → it sorts to the tail
+    await svc.set_page_number(s.id, i1, None)
+    out = await svc.list_pages(s.id)
+    assert [p["page_number"] for p in out["pages"]] == [2, 5, None]
     with pytest.raises(SeriesError):
-        await svc.reorder(s.id, [i1, i2])
-    with pytest.raises(SeriesError):
-        await svc.reorder(s.id, [i1, i2, i3, 99999])
+        await svc.set_page_number(s.id, 99999, 1)
 
 
 @pytest.mark.asyncio