diff --git a/src/map.js b/src/map.js
new file mode 100644
index 0000000..fcd12c8
--- /dev/null
+++ b/src/map.js
@@ -0,0 +1,35 @@
+const ACT1_LAYOUT = [
+  "encounter",
+  "encounter",
+  "campfire",
+  "encounter",
+  "elite",
+  "encounter",
+  "campfire",
+  "encounter",
+  "elite",
+  "boss",
+];
+
+export function createMap() {
+  return {
+    nodes: ACT1_LAYOUT.map((type, id) => ({ id, type, cleared: false })),
+    currentNode: 0,
+  };
+}
+
+export function advanceMap(map) {
+  const last = map.nodes.length - 1;
+  const nodes = map.nodes.map((n, i) =>
+    i === map.currentNode ? { ...n, cleared: true } : n,
+  );
+  return {
+    ...map,
+    nodes,
+    currentNode: Math.min(map.currentNode + 1, last),
+  };
+}
+
+export function getCurrentNode(map) {
+  return map.nodes[map.currentNode];
+}
diff --git a/src/map.test.js b/src/map.test.js
new file mode 100644
index 0000000..e7aba6e
--- /dev/null
+++ b/src/map.test.js
@@ -0,0 +1,81 @@
+import { describe, expect, test } from "bun:test";
+import { advanceMap, createMap, getCurrentNode } from "./map.js";
+
+describe("createMap", () => {
+  test("returns 10 nodes", () => {
+    const map = createMap();
+    expect(map.nodes).toHaveLength(10);
+  });
+
+  test("first node is encounter, last node is boss", () => {
+    const map = createMap();
+    expect(map.nodes[0].type).toBe("encounter");
+    expect(map.nodes[9].type).toBe("boss");
+  });
+
+  test("contains expected node type counts", () => {
+    const map = createMap();
+    const types = map.nodes.map((n) => n.type);
+    expect(types.filter((t) => t === "encounter")).toHaveLength(5);
+    expect(types.filter((t) => t === "campfire")).toHaveLength(2);
+    expect(types.filter((t) => t === "elite")).toHaveLength(2);
+    expect(types.filter((t) => t === "boss")).toHaveLength(1);
+  });
+
+  test("all nodes start cleared: false", () => {
+    const map = createMap();
+    expect(map.nodes.every((n) => n.cleared === false)).toBe(true);
+  });
+
+  test("each node has sequential id 0-9", () => {
+    const map = createMap();
+    map.nodes.forEach((n, i) => {
+      expect(n.id).toBe(i);
+    });
+  });
+
+  test("currentNode starts at 0", () => {
+    const map = createMap();
+    expect(map.currentNode).toBe(0);
+  });
+});
+
+describe("advanceMap", () => {
+  test("marks current node cleared and increments currentNode", () => {
+    const map = createMap();
+    const next = advanceMap(map);
+    expect(next.nodes[0].cleared).toBe(true);
+    expect(next.currentNode).toBe(1);
+  });
+
+  test("does not mutate the input map", () => {
+    const map = createMap();
+    advanceMap(map);
+    expect(map.nodes[0].cleared).toBe(false);
+    expect(map.currentNode).toBe(0);
+  });
+
+  test("does not go past last node (index 9)", () => {
+    let map = createMap();
+    for (let i = 0; i < 10; i++) {
+      map = advanceMap(map);
+    }
+    expect(map.currentNode).toBe(9);
+  });
+});
+
+describe("getCurrentNode", () => {
+  test("returns the node at currentNode index", () => {
+    const map = createMap();
+    const node = getCurrentNode(map);
+    expect(node).toBe(map.nodes[map.currentNode]);
+    expect(node.id).toBe(0);
+    expect(node.type).toBe("encounter");
+  });
+
+  test("returns correct node after advancing", () => {
+    const map = advanceMap(createMap());
+    const node = getCurrentNode(map);
+    expect(node.id).toBe(1);
+  });
+});