diff --git a/src/app.ts b/src/app.ts
new file mode 100644
index 0000000..5f75f12
--- /dev/null
+++ b/src/app.ts
@@ -0,0 +1,32 @@
+import type { ScreenName } from "./types";
+import { openDB, getProgress } from "./storage/db";
+import { initWelcomeScreen } from "./ui/screens";
+
+let db: IDBDatabase;
+
+export function showScreen(name: ScreenName): void {
+	document.querySelectorAll(".screen").forEach((el) => {
+		el.classList.remove("screen--active");
+	});
+	const target = document.getElementById(`screen-${name}`);
+	if (target) {
+		target.classList.add("screen--active");
+	}
+}
+
+export function getDB(): IDBDatabase {
+	return db;
+}
+
+export async function initApp(): Promise<void> {
+	db = await openDB();
+	const progress = await getProgress(db);
+	if (progress && progress.selectedCharacter) {
+		// Returning user — skip welcome, go to forest
+		showScreen("forest");
+	} else {
+		// First time — show welcome
+		initWelcomeScreen(db, showScreen);
+		showScreen("welcome");
+	}
+}
diff --git a/src/companion/characters.ts b/src/companion/characters.ts
new file mode 100644
index 0000000..742a5e9
--- /dev/null
+++ b/src/companion/characters.ts
@@ -0,0 +1,35 @@
+import type { CompanionType } from "../types";
+
+export interface CompanionDefinition {
+	type: CompanionType;
+	name: string;
+	emoji: string;
+	personality: string;
+}
+
+export const companions: CompanionDefinition[] = [
+	{
+		type: "fee",
+		name: "Lila",
+		emoji: "🧚",
+		personality: "Sanft, ermutigend, ein bisschen vertraeumt",
+	},
+	{
+		type: "einhorn",
+		name: "Stella",
+		emoji: "🦄",
+		personality: "Froehlich, enthusiastisch, feiert jeden kleinen Erfolg",
+	},
+	{
+		type: "fuchs",
+		name: "Finn",
+		emoji: "🦊",
+		personality: "Ruhig, weise, humorvoll",
+	},
+	{
+		type: "eule",
+		name: "Elsa",
+		emoji: "🦉",
+		personality: "Geduldig, warm, grossmuetterlich",
+	},
+];
diff --git a/src/main.ts b/src/main.ts
index 461e88e..cba4f8f 100644
--- a/src/main.ts
+++ b/src/main.ts
@@ -1,3 +1,4 @@
 import "./styles/main.css";
+import { initApp } from "./app";
 
-console.log("Zauberwald loaded");
+document.addEventListener("DOMContentLoaded", initApp);
diff --git a/src/ui/screens.ts b/src/ui/screens.ts
new file mode 100644
index 0000000..0a0350f
--- /dev/null
+++ b/src/ui/screens.ts
@@ -0,0 +1,8 @@
+import type { ScreenName } from "../types";
+
+export function initWelcomeScreen(
+	_db: IDBDatabase,
+	_navigateTo: (screen: ScreenName) => void,
+): void {
+	// Implemented in Task 2
+}