diff --git a/src/routes/series/[mangaId]/+page.svelte b/src/routes/series/[mangaId]/+page.svelte
index dfb456a..8fb6be1 100644
--- a/src/routes/series/[mangaId]/+page.svelte
+++ b/src/routes/series/[mangaId]/+page.svelte
@@ -1,33 +1,501 @@
 <script lang="ts">
-  import { page } from '$app/state'
+  import { goto } from '$app/navigation'
+  import { BookOpen, DownloadSimple, Circle, CheckCircle } from 'phosphor-svelte'
+  import type { Chapter } from '$lib/types/chapter'
+  import { markRead } from '$lib/request-manager/chapters'
+  import { filteredChapters, seriesState } from '$lib/state/series.svelte'
+  import { readerState } from '$lib/state/reader.svelte'
+  import Thumbnail from '$lib/ui/manga/Thumbnail.svelte'
+  import type { PageData } from './$types'
 
-  const mangaId = $derived(page.params.mangaId)
+  let { data }: { data: PageData } = $props()
+
+  const totalCount = $derived(seriesState.chapters.length)
+  const readCount = $derived(seriesState.chapters.filter(ch => ch.read).length)
+  const downloadedCount = $derived(seriesState.chapters.filter(ch => ch.downloaded).length)
+  const progressPct = $derived(totalCount > 0 ? (readCount / totalCount) * 100 : 0)
+
+  const continueChapter = $derived.by(() => {
+    if (seriesState.chapters.length === 0) return null
+
+    const ordered = [...seriesState.chapters].sort((a, b) => a.sourceOrder - b.sourceOrder)
+    const inProgress = ordered.find(ch => !ch.read && (ch.lastPageRead ?? 0) > 0)
+    if (inProgress) return inProgress
+    return ordered.find(ch => !ch.read) ?? ordered[0]
+  })
+
+  const statusText = $derived(
+    seriesState.current?.status
+      ? seriesState.current.status
+          .toLowerCase()
+          .replaceAll('_', ' ')
+          .replace(/(^|\s)\w/g, (c: string) => c.toUpperCase())
+      : 'Unknown'
+  )
+
+  $effect(() => {
+    seriesState.current = data.manga
+    seriesState.chapters = data.chapters
+    seriesState.error = null
+    seriesState.chaptersError = null
+
+    readerState.manga = data.manga
+    readerState.chapters = data.chapters
+  })
+
+  function formatChapterNumber(chapter: Chapter): string {
+    const num = chapter.chapterNumber
+    return Number.isInteger(num) ? String(num) : String(num)
+  }
+
+  function openChapter(chapter: Chapter) {
+    if (!seriesState.current) return
+
+    readerState.manga = seriesState.current
+    readerState.chapter = chapter
+    readerState.chapters = seriesState.chapters
+    readerState.pages = []
+    readerState.currentPage = 0
+
+    void goto(`/reader/${seriesState.current.id}/${chapter.id}`)
+  }
+
+  async function toggleChapterRead(chapter: Chapter) {
+    await markRead(String(chapter.id), !chapter.read)
+  }
 </script>
 
-<section class="series-placeholder">
-  <h1>Series</h1>
-  <p>Selected manga id: {mangaId}</p>
-  <p>Series detail UI will be implemented in Phase 4.</p>
+<section class="series-page">
+  {#if seriesState.current}
+    <aside class="series-meta">
+      <Thumbnail
+        class="series-cover"
+        src={seriesState.current.thumbnailUrl}
+        alt={seriesState.current.title}
+        loading="eager"
+      />
+
+      <div class="meta-body">
+        <h1>{seriesState.current.title}</h1>
+        <p class="meta-line">{statusText} · {seriesState.current.source?.displayName ?? 'Unknown source'}</p>
+        {#if seriesState.current.author || seriesState.current.artist}
+          <p class="meta-line">
+            {[seriesState.current.author, seriesState.current.artist]
+              .filter(Boolean)
+              .filter((value, idx, list) => list.indexOf(value) === idx)
+              .join(' · ')}
+          </p>
+        {/if}
+      </div>
+
+      <div class="series-progress">
+        <div class="progress-row">
+          <span>{readCount} / {totalCount} read</span>
+          <span>{Math.round(progressPct)}%</span>
+        </div>
+        <div class="progress-track">
+          <div class="progress-fill" style={`width: ${progressPct}%`}></div>
+        </div>
+        <div class="counts">
+          <span><BookOpen size={13} weight="light" /> {totalCount}</span>
+          <span><DownloadSimple size={13} weight="light" /> {downloadedCount}</span>
+        </div>
+      </div>
+
+      {#if continueChapter}
+        <button class="continue" type="button" onclick={() => openChapter(continueChapter)}>
+          Continue · Ch. {formatChapterNumber(continueChapter)}
+        </button>
+      {/if}
+    </aside>
+
+    <div class="series-content">
+      <header class="toolbar">
+        <div class="toolbar-title">
+          <h2>Chapters</h2>
+          <p>{filteredChapters.length} visible</p>
+        </div>
+
+        <div class="toolbar-controls">
+          <label class="search">
+            <span>Search</span>
+            <input
+              type="search"
+              placeholder="Filter chapter name"
+              bind:value={seriesState.chapterFilter.query}
+            />
+          </label>
+
+          <label class="toggle">
+            <input type="checkbox" bind:checked={seriesState.chapterFilter.unread} />
+            <span>Unread only</span>
+          </label>
+
+          <label class="toggle">
+            <input type="checkbox" bind:checked={seriesState.chapterFilter.downloaded} />
+            <span>Downloaded only</span>
+          </label>
+
+          <button
+            class="sort-btn"
+            type="button"
+            onclick={() => (seriesState.chapterSortDesc = !seriesState.chapterSortDesc)}
+          >
+            Sort: {seriesState.chapterSortDesc ? 'Newest' : 'Oldest'}
+          </button>
+        </div>
+      </header>
+
+      {#if seriesState.chaptersLoading}
+        <div class="empty">Loading chapters...</div>
+      {:else if filteredChapters.length === 0}
+        <div class="empty">No chapters match the current filters.</div>
+      {:else}
+        <ul class="chapter-list">
+          {#each filteredChapters as chapter (chapter.id)}
+            <li class="chapter-row" class:read={chapter.read}>
+              <button class="chapter-open" type="button" onclick={() => openChapter(chapter)}>
+                <span class="chapter-name">{chapter.name}</span>
+                <span class="chapter-meta">Ch. {formatChapterNumber(chapter)}</span>
+              </button>
+
+              <div class="chapter-actions">
+                {#if chapter.downloaded}
+                  <span class="downloaded-pill">Downloaded</span>
+                {/if}
+                <button
+                  class="mark-read"
+                  type="button"
+                  onclick={() => toggleChapterRead(chapter)}
+                  aria-label={chapter.read ? 'Mark chapter unread' : 'Mark chapter read'}
+                >
+                  {#if chapter.read}
+                    <CheckCircle size={16} weight="fill" />
+                  {:else}
+                    <Circle size={16} weight="light" />
+                  {/if}
+                </button>
+              </div>
+            </li>
+          {/each}
+        </ul>
+      {/if}
+    </div>
+  {:else}
+    <div class="empty">Could not load this series.</div>
+  {/if}
 </section>
 
 <style>
-  .series-placeholder {
-    display: flex;
-    flex-direction: column;
-    gap: var(--sp-3);
+  .series-page {
+    display: grid;
+    grid-template-columns: minmax(220px, 300px) 1fr;
+    gap: var(--sp-4);
     height: 100%;
     padding: var(--sp-6);
+    overflow: hidden;
   }
 
-  h1 {
+  .series-meta,
+  .series-content {
+    min-height: 0;
+    border: 1px solid var(--border-dim);
+    border-radius: var(--radius-xl);
+    background: var(--bg-raised);
+  }
+
+  .series-meta {
+    display: flex;
+    flex-direction: column;
+    gap: var(--sp-4);
+    padding: var(--sp-4);
+    overflow: auto;
+  }
+
+  :global(.series-cover) {
+    width: 100%;
+    aspect-ratio: 3 / 4;
+    border-radius: var(--radius-lg);
+    object-fit: cover;
+    border: 1px solid var(--border-dim);
+  }
+
+  .meta-body {
+    display: flex;
+    flex-direction: column;
+    gap: var(--sp-2);
+  }
+
+  .meta-body h1 {
     margin: 0;
     color: var(--text-primary);
     font-family: var(--font-display);
-    font-size: var(--text-2xl);
+    font-size: var(--text-xl);
+    line-height: var(--leading-tight);
   }
 
-  p {
+  .meta-line {
     margin: 0;
     color: var(--text-muted);
+    font-family: var(--font-ui);
+    font-size: var(--text-xs);
+  }
+
+  .series-progress {
+    display: flex;
+    flex-direction: column;
+    gap: var(--sp-2);
+  }
+
+  .progress-row {
+    display: flex;
+    justify-content: space-between;
+    color: var(--text-faint);
+    font-family: var(--font-ui);
+    font-size: var(--text-xs);
+    letter-spacing: var(--tracking-wide);
+    text-transform: uppercase;
+  }
+
+  .progress-track {
+    width: 100%;
+    height: 8px;
+    border-radius: 999px;
+    background: var(--bg-overlay);
+    overflow: hidden;
+  }
+
+  .progress-fill {
+    height: 100%;
+    border-radius: inherit;
+    background: var(--accent);
+  }
+
+  .counts {
+    display: flex;
+    gap: var(--sp-2);
+    color: var(--text-faint);
+    font-family: var(--font-ui);
+    font-size: var(--text-2xs);
+  }
+
+  .counts span {
+    display: inline-flex;
+    align-items: center;
+    gap: 4px;
+  }
+
+  .continue {
+    height: 36px;
+    border-radius: var(--radius-md);
+    border: 1px solid var(--accent);
+    background: var(--accent);
+    color: var(--accent-fg);
+    font-family: var(--font-ui);
+    font-size: var(--text-xs);
+    letter-spacing: var(--tracking-wide);
+    cursor: pointer;
+  }
+
+  .series-content {
+    display: flex;
+    flex-direction: column;
+    min-height: 0;
+  }
+
+  .toolbar {
+    display: flex;
+    flex-wrap: wrap;
+    justify-content: space-between;
+    gap: var(--sp-3);
+    padding: var(--sp-4);
+    border-bottom: 1px solid var(--border-dim);
+  }
+
+  .toolbar-title h2 {
+    margin: 0;
+    color: var(--text-primary);
+    font-family: var(--font-display);
+    font-size: var(--text-xl);
+  }
+
+  .toolbar-title p {
+    margin: var(--sp-1) 0 0;
+    color: var(--text-faint);
+    font-family: var(--font-ui);
+    font-size: var(--text-2xs);
+    letter-spacing: var(--tracking-wide);
+    text-transform: uppercase;
+  }
+
+  .toolbar-controls {
+    display: flex;
+    flex-wrap: wrap;
+    align-items: end;
+    gap: var(--sp-2);
+  }
+
+  .search {
+    display: flex;
+    flex-direction: column;
+    gap: 6px;
+  }
+
+  .search span {
+    color: var(--text-faint);
+    font-family: var(--font-ui);
+    font-size: var(--text-2xs);
+    letter-spacing: var(--tracking-wider);
+    text-transform: uppercase;
+  }
+
+  .search input {
+    height: 34px;
+    min-width: 180px;
+    border-radius: var(--radius-md);
+    border: 1px solid var(--border-dim);
+    background: var(--bg-base);
+    color: var(--text-primary);
+    padding: 0 10px;
+    font-family: var(--font-ui);
+    font-size: var(--text-sm);
+  }
+
+  .toggle {
+    display: inline-flex;
+    align-items: center;
+    gap: 6px;
+    height: 34px;
+    padding: 0 10px;
+    border-radius: var(--radius-md);
+    border: 1px solid var(--border-dim);
+    color: var(--text-muted);
+    font-family: var(--font-ui);
+    font-size: var(--text-xs);
+    background: var(--bg-base);
+  }
+
+  .sort-btn {
+    height: 34px;
+    padding: 0 10px;
+    border-radius: var(--radius-md);
+    border: 1px solid var(--border-dim);
+    background: var(--bg-base);
+    color: var(--text-muted);
+    font-family: var(--font-ui);
+    font-size: var(--text-xs);
+    cursor: pointer;
+  }
+
+  .chapter-list {
+    margin: 0;
+    padding: 0;
+    list-style: none;
+    overflow: auto;
+  }
+
+  .chapter-row {
+    display: flex;
+    align-items: center;
+    justify-content: space-between;
+    gap: var(--sp-2);
+    padding: 10px var(--sp-4);
+    border-bottom: 1px solid var(--border-dim);
+  }
+
+  .chapter-row.read {
+    opacity: 0.56;
+  }
+
+  .chapter-open {
+    min-width: 0;
+    flex: 1;
+    display: flex;
+    flex-direction: column;
+    align-items: flex-start;
+    gap: 2px;
+    background: transparent;
+    border: 0;
+    padding: 0;
+    text-align: left;
+    cursor: pointer;
+  }
+
+  .chapter-name {
+    max-width: 100%;
+    color: var(--text-primary);
+    font-size: var(--text-sm);
+    white-space: nowrap;
+    overflow: hidden;
+    text-overflow: ellipsis;
+  }
+
+  .chapter-meta {
+    color: var(--text-faint);
+    font-family: var(--font-ui);
+    font-size: var(--text-2xs);
+    letter-spacing: var(--tracking-wide);
+    text-transform: uppercase;
+  }
+
+  .chapter-actions {
+    display: inline-flex;
+    align-items: center;
+    gap: var(--sp-2);
+  }
+
+  .downloaded-pill {
+    display: inline-flex;
+    align-items: center;
+    height: 20px;
+    padding: 0 8px;
+    border-radius: 999px;
+    border: 1px solid var(--accent-dim);
+    background: var(--accent-muted);
+    color: var(--accent-fg);
+    font-family: var(--font-ui);
+    font-size: 10px;
+    letter-spacing: var(--tracking-wide);
+    text-transform: uppercase;
+  }
+
+  .mark-read {
+    display: inline-flex;
+    align-items: center;
+    justify-content: center;
+    width: 28px;
+    height: 28px;
+    border-radius: var(--radius-sm);
+    border: 1px solid var(--border-dim);
+    background: var(--bg-base);
+    color: var(--text-faint);
+    cursor: pointer;
+  }
+
+  .empty {
+    display: flex;
+    align-items: center;
+    justify-content: center;
+    min-height: 160px;
+    padding: var(--sp-4);
+    color: var(--text-muted);
+    font-family: var(--font-ui);
+    font-size: var(--text-sm);
+  }
+
+  @media (max-width: 960px) {
+    .series-page {
+      grid-template-columns: 1fr;
+      overflow: auto;
+    }
+
+    .series-meta,
+    .series-content {
+      overflow: visible;
+    }
+
+    .chapter-list {
+      overflow: visible;
+    }
   }
 </style>
diff --git a/src/routes/series/[mangaId]/+page.ts b/src/routes/series/[mangaId]/+page.ts
new file mode 100644
index 0000000..a6135ef
--- /dev/null
+++ b/src/routes/series/[mangaId]/+page.ts
@@ -0,0 +1,48 @@
+import { error } from '@sveltejs/kit'
+import type { PageLoad } from './$types'
+import { getAdapter } from '$lib/request-manager'
+import { seriesState } from '$lib/state/series.svelte'
+import { readerState } from '$lib/state/reader.svelte'
+
+export const load: PageLoad = async ({ params }) => {
+  const mangaId = params.mangaId
+
+  if (!mangaId) {
+    throw error(400, 'Missing manga id')
+  }
+
+  try {
+    seriesState.loading = true
+    seriesState.error = null
+    seriesState.chaptersLoading = true
+    seriesState.chaptersError = null
+
+    const adapter = getAdapter()
+    const [manga, chapters] = await Promise.all([
+      adapter.getManga(mangaId),
+      adapter.getChapters(mangaId),
+    ])
+
+    seriesState.current = manga
+    seriesState.chapters = chapters
+
+    readerState.manga = manga
+    readerState.chapters = chapters
+
+    return {
+      manga,
+      chapters,
+      mangaId,
+    }
+  } catch (err) {
+    const message = err instanceof Error ? err.message : String(err)
+
+    seriesState.error = message
+    seriesState.chaptersError = message
+
+    throw error(500, message)
+  } finally {
+    seriesState.loading = false
+    seriesState.chaptersLoading = false
+  }
+}
\ No newline at end of file