Ola arrived at school a little earlier than usual. The corridors were still empty and quiet laughter could be heard from the classrooms. Suddenly, as she approached her locker, she heard a quiet: dzyń, dzyń! She looked around, but no one was there. At that moment Max, her best friend, approached her. - Did you hear that? - Ola whispered. - Some kind of bell? - Max furrowed his eyebrows. - 'Maybe someone left a toy in the cupboard? They put their ears to the metal door. Ding, ding.... the sound was even clearer! The cupboard shuddered and a blue light emanated from a small crack. Ola and Max looked at each other with wide-open eyes. - 'Should we open it? - Max asked in a whisper. Ola took a deep breath and slowly pulled out the key. Their hearts were beating faster and faster... Suddenly the cupboard swung open slightly and....