A vibrant cartoon with colours and smooth animation. Create an original 20-second vertical 9:16 3D animated children's short video. IMPORTANT: Use completely original child characters, original toy designs and an original environment. Do not copy or recreate any existing children's cartoon characters, logos, costumes, scenes or copyrighted designs. VISUAL STYLE: High-quality colorful 3D children's animation, soft rounded shapes, expressive friendly faces, big bright eyes, colorful toy-like environment, cheerful lighting, clean polished CGI, playful and wholesome atmosphere. No text, no logos, no watermark. MAIN CHARACTER: A cute little girl with dark curly hair, wearing a bright orange overall and a yellow shirt. She has an expressive happy face and natural childlike proportions. SECOND CHARACTER: A small cute brown teddy bear wearing a tiny blue backpack. MAIN OBJECT: A small original yellow toy school bus with rounded shapes and colorful details. SCENE 1 - 0-2 seconds: Close-up. The little girl stands beside the yellow toy school bus while holding the teddy bear. Bright colorful playground street in the background. She smiles excitedly and prepares to put the teddy bear inside. SCENE 2 - 2-5 seconds: Medium shot. She gently places the teddy bear onto a bus seat, closes the bus door and waves goodbye. The teddy bear looks through the window. SCENE 3 - 5-8 seconds: Unexpected action. The toy bus suddenly starts moving by itself very slowly. The girl's smile disappears and she looks surprised. She starts running after it. SCENE 4 - 8-11 seconds: Tracking shot. The yellow bus drives around the corner of a colorful little street and disappears behind a bright blue fence. The girl runs after it. SCENE 5 - 11-14 seconds: The girl reaches the corner but the bus is completely gone. She looks left and right in confusion. On the ground she notices a tiny yellow toy piece. SCENE 6 - 14-17 seconds: Close-up of her hand picking up the yellow piece. Suddenly we hear a cheerful toy bus horn from behind a nearby colorful garage door. She slowly turns around. SCENE 7 - 17-20 seconds: Slow cinematic push-in toward the garage door. The door begins opening very slowly. A large mysterious silhouette shaped like a bus appears inside. Do NOT reveal what is inside. The girl's eyes become wide with surprise. END: Cut suddenly to a clean dark screen at exactly 20 seconds, leaving the mystery unresolved. CAMERA: Smooth child-friendly camera movement, quick cuts during action, close-ups for reactions, cinematic push-in at the ending. SOUND: Cheerful playful children's background music, soft footsteps, toy wheels rolling, one cute bus horn sound, subtle suspenseful sound during the final 3 seconds. MOOD: Cute, funny, colorful, mysterious but NOT scary. The final shot must create curiosity and make viewers want to see Part 2.