diff --git a/.env.example b/.env.example
index b4214c8..37913dc 100644
--- a/.env.example
+++ b/.env.example
@@ -4,3 +4,6 @@
 # set the same variables in your Cloudflare build environment for deploys.
 PUBLIC_AUTH0_DOMAIN=id.letsbuilda.dev
 PUBLIC_AUTH0_CLIENT_ID=THoRnVJxMOfLxMAW0kaNW8nuP1q8q3qQ
+PUBLIC_AUTH0_AUDIENCE=https://mundane.letsbuilda.dev
+# The Mundane API (letsbuilda/mundane-backend). Locally: http://localhost:8787 (pywrangler dev).
+PUBLIC_MUNDANE_API_URL=https://mundane.letsbuilda.dev
diff --git a/README.md b/README.md
index 5991171..c8ba57f 100644
--- a/README.md
+++ b/README.md
@@ -48,6 +48,8 @@ non-secret** environment variables:
 | :----------------------- | :--------------------------- |
 | `PUBLIC_AUTH0_DOMAIN`    | Auth0 tenant domain          |
 | `PUBLIC_AUTH0_CLIENT_ID` | Auth0 SPA application client ID |
+| `PUBLIC_AUTH0_AUDIENCE`  | Auth0 API identifier for the Mundane backend |
+| `PUBLIC_MUNDANE_API_URL` | Base URL of the Mundane API  |
 
 Copy `.env.example` to `.env` for local development, and set the same variables
 in the Cloudflare build environment for deploys (Astro inlines `PUBLIC_*` values
@@ -58,6 +60,12 @@ In the Auth0 application (type: **Single Page Application**), add both your loca
 **Allowed Callback URLs**, **Allowed Logout URLs**, and **Allowed Web Origins**,
 and enable **Refresh Token Rotation**.
 
+The `/mundane` page plays [Mundane](https://github.com/letsbuilda/mundane) against
+[`mundane-backend`](https://github.com/letsbuilda/mundane-backend), sending the
+player's access token with every request. That needs an Auth0 **API** with identifier
+`https://mundane.letsbuilda.dev` (RS256) and **Allow Offline Access** turned on, so
+the SPA's refresh tokens work for it.
+
 ## 👀 Want to learn more?
 
 Feel free to check [our documentation](https://docs.astro.build) or jump into our [Discord server](https://astro.build/chat).
diff --git a/public/css/main.css b/public/css/main.css
index 4cff3b7..9ec9e12 100644
--- a/public/css/main.css
+++ b/public/css/main.css
@@ -85,3 +85,39 @@ main {
   margin: 0;
   word-break: break-word;
 }
+
+.mundane-players {
+  display: grid;
+  grid-template-columns: repeat(auto-fit, minmax(14rem, 1fr));
+  gap: 1rem;
+}
+
+.mundane-player {
+  padding: 1rem;
+  border: 1px solid #e2e2e2;
+  border-radius: 12px;
+}
+
+.mundane-player h2,
+.mundane-player h3 {
+  margin: 0 0 0.5rem;
+}
+
+.mundane-button {
+  cursor: pointer;
+  margin: 0.25rem 0.25rem 0 0;
+  padding: 0.3rem 0.8rem;
+  border: 1px solid #d1d5db;
+  border-radius: 6px;
+  background: #f9fafb;
+  font: inherit;
+}
+
+.mundane-button:disabled {
+  cursor: not-allowed;
+  opacity: 0.5;
+}
+
+.mundane-error {
+  color: #b91c1c;
+}
diff --git a/public/favicon.svg b/public/favicon.svg
index f157bd1..5b67f46 100644
--- a/public/favicon.svg
+++ b/public/favicon.svg
@@ -1,4 +1,5 @@
 <svg xmlns="http://www.w3.org/2000/svg" fill="none" viewBox="0 0 128 128">
+    <title>letsbuilda.dev</title>
     <path d="M50.4 78.5a75.1 75.1 0 0 0-28.5 6.9l24.2-65.7c.7-2 1.9-3.2 3.4-3.2h29c1.5 0 2.7 1.2 3.4 3.2l24.2 65.7s-11.6-7-28.5-7L67 45.5c-.4-1.7-1.6-2.8-2.9-2.8-1.3 0-2.5 1.1-2.9 2.7L50.4 78.5Zm-1.1 28.2Zm-4.2-20.2c-2 6.6-.6 15.8 4.2 20.2a17.5 17.5 0 0 1 .2-.7 5.5 5.5 0 0 1 5.7-4.5c2.8.1 4.3 1.5 4.7 4.7.2 1.1.2 2.3.2 3.5v.4c0 2.7.7 5.2 2.2 7.4a13 13 0 0 0 5.7 4.9v-.3l-.2-.3c-1.8-5.6-.5-9.5 4.4-12.8l1.5-1a73 73 0 0 0 3.2-2.2 16 16 0 0 0 6.8-11.4c.3-2 .1-4-.6-6l-.8.6-1.6 1a37 37 0 0 1-22.4 2.7c-5-.7-9.7-2-13.2-6.2Z" />
     <style>
         path { fill: #000; }
diff --git a/src/env.d.ts b/src/env.d.ts
index 765ab4b..27a8302 100644
--- a/src/env.d.ts
+++ b/src/env.d.ts
@@ -5,6 +5,10 @@ interface ImportMetaEnv {
   readonly PUBLIC_AUTH0_DOMAIN: string;
   /** Auth0 SPA application client ID. Public, non-secret. */
   readonly PUBLIC_AUTH0_CLIENT_ID: string;
+  /** Auth0 API identifier the backend accepts tokens for. Public, non-secret. */
+  readonly PUBLIC_AUTH0_AUDIENCE: string;
+  /** Base URL of the Mundane API. Public, non-secret. */
+  readonly PUBLIC_MUNDANE_API_URL: string;
 }
 
 interface ImportMeta {
diff --git a/src/layouts/BaseLayout.astro b/src/layouts/BaseLayout.astro
index 3c922ea..858e4b8 100644
--- a/src/layouts/BaseLayout.astro
+++ b/src/layouts/BaseLayout.astro
@@ -19,6 +19,7 @@ const { title } = Astro.props;
   <body>
     <nav>
       <a href="/">Home</a>
+      <a href="/mundane">Mundane</a>
       <a href="/account">Account</a>
       <span class="nav-spacer"></span>
       <button id="btn-login" type="button" hidden>Log in</button>
diff --git a/src/lib/auth.ts b/src/lib/auth.ts
index 3802978..2bb5bb7 100644
--- a/src/lib/auth.ts
+++ b/src/lib/auth.ts
@@ -9,10 +9,12 @@ import {
 // variables (see .env.example).
 const domain = import.meta.env.PUBLIC_AUTH0_DOMAIN;
 const clientId = import.meta.env.PUBLIC_AUTH0_CLIENT_ID;
+// The Auth0 API that access tokens are minted for: the Mundane backend.
+const audience = import.meta.env.PUBLIC_AUTH0_AUDIENCE;
 
-if (!domain || !clientId) {
+if (!domain || !clientId || !audience) {
   throw new Error(
-    "Missing Auth0 configuration. Set PUBLIC_AUTH0_DOMAIN and PUBLIC_AUTH0_CLIENT_ID.",
+    "Missing Auth0 configuration. Set PUBLIC_AUTH0_DOMAIN, PUBLIC_AUTH0_CLIENT_ID and PUBLIC_AUTH0_AUDIENCE.",
   );
 }
 
@@ -55,6 +57,7 @@ async function bootstrap(): Promise<Auth0Client> {
     cacheLocation: "localstorage",
     authorizationParams: {
       redirect_uri: window.location.origin,
+      audience,
       scope: "openid profile email",
     },
   });
@@ -87,6 +90,12 @@ export async function getUser(): Promise<User | undefined> {
   return client.getUser();
 }
 
+// An access token for the backend API (`audience`), refreshed silently as needed.
+export async function getAccessToken(): Promise<string> {
+  const client = await getClient();
+  return client.getTokenSilently();
+}
+
 // Redirect to Auth0 to log in, returning to `returnTo` afterwards.
 export async function login(
   returnTo: string = window.location.pathname,
diff --git a/src/lib/mundane.ts b/src/lib/mundane.ts
new file mode 100644
index 0000000..095d1aa
--- /dev/null
+++ b/src/lib/mundane.ts
@@ -0,0 +1,91 @@
+import { getAccessToken } from "./auth";
+
+// Client for the Mundane API (letsbuilda/mundane-backend). Every call carries
+// the signed-in player's access token; games belong to whoever created them.
+const apiUrl = import.meta.env.PUBLIC_MUNDANE_API_URL;
+
+if (!apiUrl) {
+  throw new Error("Missing Mundane configuration. Set PUBLIC_MUNDANE_API_URL.");
+}
+
+export interface Player {
+  name: string;
+  composure: number;
+  time: number;
+  hand: string[];
+  board: string[];
+  deck: string[];
+  discard: string[];
+}
+
+export interface StackItem {
+  id: number;
+  card_id: string;
+  controller: number;
+  target_id: number | null;
+}
+
+export interface GameState {
+  players: Player[];
+  active_player: number;
+  priority_player: number;
+  phase: string;
+  stack: StackItem[];
+  turn: number;
+  winner: number | null;
+}
+
+export type Action =
+  | { type: "play_card"; player: number; hand_index: number }
+  | {
+      type: "cast_instant";
+      player: number;
+      hand_index: number;
+      target_id?: number | null;
+    }
+  | { type: "pass_priority"; player: number };
+
+// The API's error body (`detail`) is the reason a move was refused.
+export class MundaneError extends Error {
+  constructor(
+    readonly status: number,
+    detail: string,
+  ) {
+    super(detail);
+  }
+}
+
+async function call<T>(path: string, body?: unknown): Promise<T> {
+  const headers: Record<string, string> = {
+    Authorization: `Bearer ${await getAccessToken()}`,
+  };
+  const init: RequestInit = { method: body === undefined ? "GET" : "POST" };
+  if (body !== undefined) {
+    headers["Content-Type"] = "application/json";
+    init.body = JSON.stringify(body);
+  }
+  init.headers = headers;
+
+  const response = await fetch(`${apiUrl}${path}`, init);
+  const payload: unknown = await response.json();
+  if (!response.ok) {
+    const detail = (payload as { detail?: string }).detail;
+    throw new MundaneError(response.status, detail ?? "Request failed");
+  }
+  return payload as T;
+}
+
+export function createGame(): Promise<{ game_id: string; state: GameState }> {
+  return call("/games", {});
+}
+
+export function readGame(gameId: string): Promise<GameState> {
+  return call(`/games/${encodeURIComponent(gameId)}`);
+}
+
+export function submitAction(
+  gameId: string,
+  action: Action,
+): Promise<GameState> {
+  return call(`/games/${encodeURIComponent(gameId)}/actions`, action);
+}
diff --git a/src/pages/mundane.astro b/src/pages/mundane.astro
new file mode 100644
index 0000000..b690814
--- /dev/null
+++ b/src/pages/mundane.astro
@@ -0,0 +1,160 @@
+---
+import BaseLayout from "../layouts/BaseLayout.astro";
+---
+
+<BaseLayout title="Mundane · letsbuilda.dev">
+  <h1>Mundane</h1>
+  <p>No dragons. No spells. Just Tuesday.</p>
+
+  <p id="mundane-status">Loading&hellip;</p>
+  <button id="mundane-new" type="button" class="mundane-button" hidden>
+    New game
+  </button>
+
+  <section id="mundane-game" hidden>
+    <p id="mundane-turn"></p>
+    <div id="mundane-players" class="mundane-players"></div>
+    <h2>Stack</h2>
+    <ol id="mundane-stack"></ol>
+    <button id="mundane-pass" type="button" class="mundane-button">
+      Pass priority
+    </button>
+    <p id="mundane-error" class="mundane-error" role="alert"></p>
+  </section>
+
+  <script>
+    import { isAuthenticated, login } from "../lib/auth";
+    import {
+      type Action,
+      createGame,
+      type GameState,
+      MundaneError,
+      readGame,
+      submitAction,
+    } from "../lib/mundane";
+
+    const status = document.getElementById("mundane-status");
+    const newButton = document.getElementById("mundane-new");
+    const gameSection = document.getElementById("mundane-game");
+    const errorLine = document.getElementById("mundane-error");
+
+    // textContent (never innerHTML) keeps API values inert.
+    const el = (tag: string, text = ""): HTMLElement => {
+      const node = document.createElement(tag);
+      node.textContent = text;
+      return node;
+    };
+
+    let gameId = new URLSearchParams(window.location.search).get("game");
+
+    function showError(error: unknown) {
+      if (errorLine) {
+        errorLine.textContent =
+          error instanceof MundaneError ? error.message : String(error);
+      }
+    }
+
+    async function act(action: Action) {
+      if (!gameId) return;
+      try {
+        render(await submitAction(gameId, action));
+      } catch (error) {
+        showError(error);
+      }
+    }
+
+    function render(state: GameState) {
+      if (errorLine) errorLine.textContent = "";
+      const turn = document.getElementById("mundane-turn");
+      if (turn) {
+        const priority = state.players[state.priority_player]?.name ?? "";
+        turn.textContent =
+          state.winner === null
+            ? `Turn ${state.turn}, ${state.phase}. ${priority} has priority.`
+            : `${state.players[state.winner]?.name} wins!`;
+      }
+
+      const players = document.getElementById("mundane-players");
+      players?.replaceChildren(
+        ...state.players.map((player, index) => {
+          const card = el("article");
+          card.className = "mundane-player";
+          card.append(
+            el("h2", player.name),
+            el("p", `Composure ${player.composure} · Time ${player.time}`),
+            el("p", `Board: ${player.board.join(", ") || "—"}`),
+          );
+          const hand = el("ul");
+          player.hand.forEach((cardId, handIndex) => {
+            const item = el("li", `${cardId} `);
+            const mine = index === state.priority_player && state.winner === null;
+            for (const [label, type] of [
+              ["Play", "play_card"],
+              ["Cast", "cast_instant"],
+            ] as const) {
+              const button = el("button", label) as HTMLButtonElement;
+              button.type = "button";
+              button.className = "mundane-button";
+              button.disabled = !mine;
+              button.addEventListener("click", () =>
+                act({ type, player: index, hand_index: handIndex }),
+              );
+              item.append(button);
+            }
+            hand.append(item);
+          });
+          card.append(el("h3", "Hand"), hand);
+          return card;
+        }),
+      );
+
+      const stack = document.getElementById("mundane-stack");
+      stack?.replaceChildren(
+        ...state.stack.map((item) =>
+          el(
+            "li",
+            `${item.card_id} (${state.players[item.controller]?.name ?? "?"})`,
+          ),
+        ),
+      );
+
+      const pass = document.getElementById("mundane-pass");
+      if (pass instanceof HTMLButtonElement) {
+        pass.disabled = state.winner !== null;
+        pass.onclick = () =>
+          act({ type: "pass_priority", player: state.priority_player });
+      }
+
+      gameSection?.removeAttribute("hidden");
+    }
+
+    newButton?.addEventListener("click", async () => {
+      try {
+        const created = await createGame();
+        gameId = created.game_id;
+        const url = new URL(window.location.href);
+        url.searchParams.set("game", gameId);
+        window.history.replaceState({}, "", url);
+        render(created.state);
+      } catch (error) {
+        showError(error);
+        if (status) status.textContent = String(error);
+      }
+    });
+
+    if (!(await isAuthenticated())) {
+      // Gated page: games belong to a signed-in player.
+      await login(window.location.pathname + window.location.search);
+    } else {
+      newButton?.removeAttribute("hidden");
+      if (status) status.textContent = "";
+      if (gameId) {
+        try {
+          render(await readGame(gameId));
+        } catch (error) {
+          if (status) status.textContent = String(error);
+        }
+      }
+    }
+  </script>
+</BaseLayout>