diff --git a/static/player/browser-flow.test.ts b/static/player/browser-flow.test.ts
index f1416b03..8f8b87e6 100644
--- a/static/player/browser-flow.test.ts
+++ b/static/player/browser-flow.test.ts
@@ -1,13 +1,17 @@
 import assert from "node:assert/strict";
 import { before, beforeEach, describe, test } from "node:test";
 
+/* eslint-disable max-classes-per-file */
+
 class FakeElement extends EventTarget {
+  readonly dataset: Record<string, string> = {};
   className = "";
   classList = fakeClassList();
   disabled = false;
   parentElement: FakeElement | null = null;
   style: Record<string, string> = {};
   textContent = "";
+  tabIndex = 0;
   private readonly children: FakeElement[] = [];
   private readonly queries = new Map<string, FakeElement | null>();
 
@@ -16,10 +20,26 @@ class FakeElement extends EventTarget {
     this.children.push(child);
   }
 
+  closest(_selector: string): FakeElement | null {
+    return null;
+  }
+
+  focus(options?: FocusOptions): void {
+    void options;
+  }
+
   querySelector(selector: string): FakeElement | null {
     return this.queries.get(selector) ?? null;
   }
 
+  querySelectorAll(_selector: string): FakeElement[] {
+    return [];
+  }
+
+  removeAttribute(name: string): void {
+    void name;
+  }
+
   replaceChildren(...children: FakeElement[]): void {
     this.children.length = 0;
     children.forEach((child) => {
@@ -30,6 +50,52 @@ class FakeElement extends EventTarget {
   setQuery(selector: string, element: FakeElement | null): void {
     this.queries.set(selector, element);
   }
+
+  setAttribute(name: string, value: string): void {
+    void name;
+    void value;
+  }
+
+  scrollIntoView(options?: ScrollIntoViewOptions): void {
+    void options;
+  }
+}
+
+class FakeAnchorElement extends FakeElement {
+  href = "";
+  target = "";
+
+  override closest(selector: string): FakeAnchorElement | null {
+    return selector === "a[data-episode-id]" ? this : null;
+  }
+}
+
+class FakeMouseEvent {
+  readonly altKey: boolean;
+  readonly button: number;
+  readonly ctrlKey: boolean;
+  defaultPrevented = false;
+  readonly metaKey: boolean;
+  readonly shiftKey: boolean;
+  readonly target: FakeElement;
+
+  constructor(
+    target: FakeElement,
+    options: Partial<
+      Pick<MouseEvent, "altKey" | "button" | "ctrlKey" | "metaKey" | "shiftKey">
+    > = {},
+  ) {
+    this.target = target;
+    this.altKey = options.altKey ?? false;
+    this.button = options.button ?? 0;
+    this.ctrlKey = options.ctrlKey ?? false;
+    this.metaKey = options.metaKey ?? false;
+    this.shiftKey = options.shiftKey ?? false;
+  }
+
+  preventDefault(): void {
+    this.defaultPrevented = true;
+  }
 }
 
 type FakeVideoElement = FakeElement & {
@@ -48,11 +114,17 @@ type FakeVideoElement = FakeElement & {
 
 type PlayerModules = {
   completeAnime: (episodeNumber: number) => Promise<void>;
+  handleEpisodeNavigationClick: (event: MouseEvent) => boolean;
   refreshCurrentModeSource: (signal?: AbortSignal) => Promise<boolean>;
   saveProgress: (force?: boolean, progressSeconds?: number) => Promise<void>;
   setupProgress: () => void;
   state: typeof import("./state").state;
   streamUrlForMode: (mode: string, quality?: string) => string;
+  setupEpisodeNavigation: (signal: AbortSignal) => void;
+  transitionToEpisode: (
+    episode: number,
+    options?: { fallbackHref?: string; history?: "none" | "push" | "replace" },
+  ) => Promise<boolean>;
 };
 
 const emptyRanges = (): TimeRanges => ({ length: 0, end: () => 0, start: () => 0 });
@@ -127,6 +199,28 @@ const fakeDocument = (): Document & {
 };
 
 const documentStub = fakeDocument();
+const storage = (): Storage => {
+  const values = new Map<string, string>();
+  return {
+    clear: (): void => {
+      values.clear();
+    },
+    getItem: (key: string): string | null => values.get(key) ?? null,
+    key: (index: number): string | null => [...values.keys()][index] ?? null,
+    get length(): number {
+      return values.size;
+    },
+    removeItem: (key: string): void => {
+      values.delete(key);
+    },
+    setItem: (key: string, value: string): void => {
+      values.set(key, value);
+    },
+  };
+};
+const historyCalls: string[] = [];
+const localStorageStub = storage();
+const sessionStorageStub = storage();
 const windowStub = Object.assign(new EventTarget(), {
   clearTimeout: (_handle: number | undefined): void => {
     void _handle;
@@ -136,8 +230,14 @@ const windowStub = Object.assign(new EventTarget(), {
     void _delay;
     return 1;
   },
+  localStorage: localStorageStub,
+  location: { href: "http://localhost/anime/42/watch?ep=3", origin: "http://localhost" },
+  showToast: (options: { message: string }): void => {
+    void options;
+  },
 });
 let modules: PlayerModules;
+let beaconCalls: string[];
 let fetchCalls: Array<{ body?: string; url: string }>;
 let timeoutCallbacks: Array<() => void>;
 const originalConsoleError = console.error;
@@ -145,14 +245,39 @@ const originalConsoleError = console.error;
 const installBrowserGlobals = (): void => {
   Object.assign(globalThis, {
     document: documentStub,
+    Element: FakeElement,
+    HTMLAnchorElement: FakeAnchorElement,
     HTMLElement: FakeElement,
     HTMLVideoElement: FakeElement,
     HTMLMediaElement: { HAVE_METADATA: 1, HAVE_CURRENT_DATA: 2 },
+    MouseEvent: FakeMouseEvent,
     window: windowStub,
   });
+  Object.assign(globalThis, {
+    history: {
+      pushState: (_data: unknown, _unused: string, url?: string | URL | null): void => {
+        const href = String(url);
+        historyCalls.push(href);
+        windowStub.location.href = href;
+      },
+      replaceState: (_data: unknown, _unused: string, url?: string | URL | null): void => {
+        const href = String(url);
+        historyCalls.push(href);
+        windowStub.location.href = href;
+      },
+    },
+    sessionStorage: sessionStorageStub,
+  });
   Object.defineProperty(globalThis, "navigator", {
     configurable: true,
-    value: { sendBeacon: () => true },
+    value: {
+      sendBeacon: (_url: string, data: Blob): boolean => {
+        void data.text().then((value) => {
+          beaconCalls.push(value);
+        });
+        return true;
+      },
+    },
   });
 };
 
@@ -170,6 +295,7 @@ const resetPlayerState = (): void => {
   state.elements.timeDisplay = asHTMLElement(new FakeElement());
   state.elements.durationDisplay = asHTMLElement(new FakeElement());
   state.episode.current = "3";
+  state.episode.total = 10;
   state.episode.malID = 42;
   state.episode.transitionEpisode = null;
   state.episode.completionSent = false;
@@ -177,8 +303,13 @@ const resetPlayerState = (): void => {
   state.episode.endedProgressSaved = false;
   state.episode.lastSavedProgress = { episode: "3", seconds: -1 };
   state.playback.currentMode = "sub";
+  state.playback.modeSwitchedFrom = "";
+  state.playback.startTimeSeconds = 0;
   state.playback.streamURL = "/watch/proxy/stream";
   state.playback.modeSources = {};
+  state.elements.episodeGrid = null;
+  state.elements.episodeList = null;
+  state.elements.videoOverlay = null;
   state.timers.progressSaveTimer = undefined;
   documentStub.setDropdownTrigger(null);
 };
@@ -186,21 +317,27 @@ const resetPlayerState = (): void => {
 const flushPromises = async (): Promise<void> => {
   await Promise.resolve();
   await Promise.resolve();
+  await Promise.resolve();
+  await Promise.resolve();
 };
 
 const loadPlayerModules = async (): Promise<PlayerModules> => {
   const completeModule = await import("./episodes/complete");
+  const navModule = await import("./episodes/nav");
   const progressModule = await import("./progress");
   const stateModule = await import("./state");
   const sourceModule = await import("./source");
 
   return {
     completeAnime: completeModule.completeAnime,
+    handleEpisodeNavigationClick: navModule.handleEpisodeNavigationClick,
     refreshCurrentModeSource: sourceModule.refreshCurrentModeSource,
     saveProgress: progressModule.saveProgress,
     setupProgress: progressModule.setupProgress,
     state: stateModule.state,
     streamUrlForMode: sourceModule.streamUrlForMode,
+    setupEpisodeNavigation: navModule.setupEpisodeNavigation,
+    transitionToEpisode: navModule.transitionToEpisode,
   };
 };
 
@@ -212,6 +349,14 @@ before(async () => {
 beforeEach(() => {
   console.error = originalConsoleError;
   fetchCalls = [];
+  beaconCalls = [];
+  historyCalls.length = 0;
+  localStorageStub.clear();
+  sessionStorageStub.clear();
+  windowStub.location.href = "http://localhost/anime/42/watch?ep=3";
+  windowStub.showToast = (options: { message: string }): void => {
+    void options;
+  };
   timeoutCallbacks = [];
   globalThis.fetch = ((url: string, init?: RequestInit) => {
     fetchCalls.push({ url, body: typeof init?.body === "string" ? init.body : undefined });
@@ -225,6 +370,27 @@ beforeEach(() => {
   resetPlayerState();
 });
 
+const episodePayload = (
+  episode: number,
+  modes?: Record<string, { subtitles: never[]; token: string; type: string }>,
+): Record<string, unknown> => {
+  const modeSources = modes ?? {
+    dub: { subtitles: [], token: `dub-${episode}`, type: "mp4" },
+    sub: { subtitles: [], token: `sub-${episode}`, type: "mp4" },
+  };
+  return {
+    episode_title: `Episode ${episode}`,
+    initial_mode: "sub",
+    mode_sources: modeSources,
+    mode_switched_from: "",
+    segments: [],
+    start_time_seconds: 12,
+  };
+};
+
+const episodeResponse = (episode: number): Response =>
+  ({ json: () => Promise.resolve(episodePayload(episode)), ok: true, status: 200 }) as Response;
+
 describe("browser player flow", () => {
   test("builds initial stream URLs from mode token, HLS type, and preferred quality", () => {
     modules.state.playback.modeSources = {
@@ -322,4 +488,205 @@ describe("browser player flow", () => {
     assert.equal(trigger.textContent, "Completed ");
     assert.equal(errors.length, 1);
   });
+
+  test("transitions episodes in place and saves progress for the episode being left", async () => {
+    const loading = new FakeElement();
+    (modules.state.elements.container as unknown as FakeElement).setQuery(
+      "[data-loading]",
+      loading,
+    );
+    modules.state.elements.video.currentTime = 30;
+    globalThis.fetch = ((url: string) => {
+      fetchCalls.push({ url });
+      return Promise.resolve(episodeResponse(4));
+    }) as typeof fetch;
+
+    const transitioned = await modules.transitionToEpisode(4);
+    await flushPromises();
+
+    assert.equal(transitioned, true);
+    assert.deepEqual(
+      fetchCalls.map((call) => call.url),
+      ["/api/watch/episode/42/4?mode=sub"],
+    );
+    assert.equal(modules.state.episode.current, "4");
+    assert.equal(modules.state.playback.startTimeSeconds, 12);
+    assert.equal(modules.state.elements.video.src, "/watch/proxy/stream?mode=sub&token=sub-4");
+    assert.equal(loading.style.display, "flex");
+    assert.match(historyCalls[0] ?? "", /[?&]ep=4(?:&|$)/);
+    assert.deepEqual(JSON.parse(beaconCalls[0] ?? "{}"), {
+      mal_id: 42,
+      episode: 3,
+      time_seconds: 30,
+    });
+
+    modules.state.elements.video.dispatchEvent(new Event("loadedmetadata"));
+    assert.equal(modules.state.episode.transitionEpisode, null);
+  });
+
+  test("uses the same async path for episode links and leaves modified clicks native", async () => {
+    const modifiedLink = new FakeAnchorElement();
+    modifiedLink.href = "http://localhost/anime/42/watch?ep=2";
+    modifiedLink.dataset.episodeId = "2";
+    const modifiedClick = new FakeMouseEvent(modifiedLink, { metaKey: true });
+
+    assert.equal(
+      modules.handleEpisodeNavigationClick(modifiedClick as unknown as MouseEvent),
+      false,
+    );
+    assert.equal(modifiedClick.defaultPrevented, false);
+    assert.equal(fetchCalls.length, 0);
+
+    globalThis.fetch = ((url: string) => {
+      fetchCalls.push({ url });
+      const episode = Number.parseInt(
+        new URL(url, "http://localhost").pathname.split("/").at(-1) ?? "",
+        10,
+      );
+      return Promise.resolve(episodeResponse(episode));
+    }) as typeof fetch;
+    const previousLink = new FakeAnchorElement();
+    previousLink.href = "http://localhost/anime/42/watch?ep=2";
+    previousLink.dataset.episodeId = "2";
+    const previousClick = new FakeMouseEvent(previousLink);
+
+    assert.equal(
+      modules.handleEpisodeNavigationClick(previousClick as unknown as MouseEvent),
+      true,
+    );
+    assert.equal(previousClick.defaultPrevented, true);
+    await flushPromises();
+    assert.equal(modules.state.episode.current, "2");
+    modules.state.elements.video.dispatchEvent(new Event("loadedmetadata"));
+
+    const nextLink = new FakeAnchorElement();
+    nextLink.href = "http://localhost/anime/42/watch?ep=4";
+    nextLink.dataset.episodeId = "4";
+    assert.equal(
+      modules.handleEpisodeNavigationClick(new FakeMouseEvent(nextLink) as unknown as MouseEvent),
+      true,
+    );
+    await flushPromises();
+    assert.equal(modules.state.episode.current, "4");
+    modules.state.elements.video.dispatchEvent(new Event("loadedmetadata"));
+  });
+
+  test("aborts a stale episode request and commits only the latest selection", async () => {
+    modules.state.episode.current = "1";
+    windowStub.location.href = "http://localhost/anime/42/watch?ep=1";
+    const pending = new Map<
+      number,
+      { reject: (reason: unknown) => void; resolve: (response: Response) => void }
+    >();
+    globalThis.fetch = ((url: string, init?: RequestInit) => {
+      fetchCalls.push({ url });
+      const episode = Number.parseInt(
+        new URL(url, "http://localhost").pathname.split("/").at(-1) ?? "",
+        10,
+      );
+      return new Promise<Response>((resolve, reject) => {
+        pending.set(episode, { reject, resolve });
+        init?.signal?.addEventListener("abort", () => {
+          reject(new DOMException("aborted", "AbortError"));
+        });
+      });
+    }) as typeof fetch;
+
+    const episode2 = modules.transitionToEpisode(2);
+    const episode3 = modules.transitionToEpisode(3);
+    pending.get(3)?.resolve(episodeResponse(3));
+
+    assert.equal(await episode3, true);
+    assert.equal(await episode2, false);
+    assert.equal(modules.state.episode.current, "3");
+    assert.equal(modules.state.elements.video.src, "/watch/proxy/stream?mode=sub&token=sub-3");
+    assert.equal(historyCalls.length, 1);
+    assert.match(historyCalls[0] ?? "", /[?&]ep=3(?:&|$)/);
+    modules.state.elements.video.dispatchEvent(new Event("loadedmetadata"));
+  });
+
+  test("falls back to the original link when the episode payload fails", async () => {
+    console.error = (): void => {
+      void 0;
+    };
+    globalThis.fetch = ((url: string) => {
+      fetchCalls.push({ url });
+      return Promise.resolve({ ok: false, status: 503 } as Response);
+    }) as typeof fetch;
+    const fallbackHref = "http://localhost/anime/42/watch?ep=5";
+
+    assert.equal(await modules.transitionToEpisode(5, { fallbackHref }), false);
+    assert.equal(windowStub.location.href, fallbackHref);
+    assert.equal(modules.state.episode.current, "3");
+  });
+
+  test("retries one failed media source before falling back to navigation", async () => {
+    console.error = (): void => {
+      void 0;
+    };
+    let request = 0;
+    globalThis.fetch = ((url: string) => {
+      fetchCalls.push({ url });
+      request += 1;
+      const payload = episodePayload(4);
+      payload.mode_sources = {
+        dub: { subtitles: [], token: `dub-${request}`, type: "mp4" },
+        sub: { subtitles: [], token: `sub-${request}`, type: "mp4" },
+      };
+      return Promise.resolve({
+        json: () => Promise.resolve(payload),
+        ok: true,
+        status: 200,
+      } as Response);
+    }) as typeof fetch;
+    const fallbackHref = "http://localhost/anime/42/watch?ep=4";
+
+    assert.equal(await modules.transitionToEpisode(4, { fallbackHref }), true);
+    assert.equal(modules.state.elements.video.src, "/watch/proxy/stream?mode=sub&token=sub-1");
+    modules.state.elements.video.dispatchEvent(new Event("error"));
+    await flushPromises();
+    assert.equal(modules.state.elements.video.src, "/watch/proxy/stream?mode=sub&token=sub-2");
+
+    modules.state.elements.video.dispatchEvent(new Event("error"));
+    assert.equal(windowStub.location.href, fallbackHref);
+  });
+
+  test("uses the returned fallback mode and restores episodes on popstate", async () => {
+    const notices: string[] = [];
+    windowStub.showToast = ({ message }: { message: string }): void => {
+      notices.push(message);
+    };
+    modules.state.playback.currentMode = "dub";
+    globalThis.fetch = ((url: string) => {
+      fetchCalls.push({ url });
+      const episode = Number.parseInt(
+        new URL(url, "http://localhost").pathname.split("/").at(-1) ?? "",
+        10,
+      );
+      const payload = episodePayload(episode, {
+        sub: { subtitles: [], token: `sub-${episode}`, type: "mp4" },
+      });
+      payload.mode_switched_from = "dub";
+      return Promise.resolve({
+        json: () => Promise.resolve(payload),
+        ok: true,
+        status: 200,
+      } as Response);
+    }) as typeof fetch;
+
+    assert.equal(await modules.transitionToEpisode(4), true);
+    assert.equal(modules.state.playback.currentMode, "sub");
+    assert.deepEqual(notices, ["Episode 4 is only available in sub, switched from dub."]);
+    modules.state.elements.video.dispatchEvent(new Event("loadedmetadata"));
+
+    const controller = new AbortController();
+    modules.setupEpisodeNavigation(controller.signal);
+    windowStub.location.href = "http://localhost/anime/42/watch?ep=2";
+    windowStub.dispatchEvent(new Event("popstate"));
+    await flushPromises();
+    assert.equal(modules.state.episode.current, "2");
+    assert.equal(historyCalls.length, 1);
+    modules.state.elements.video.dispatchEvent(new Event("loadedmetadata"));
+    controller.abort();
+  });
 });