The school's space laboratory was never a particularly popular place. It smelled of old metal and electronics, and most pupils avoided it with a wide grin. But not Zuzia and her younger brother Kacper. Zuzia was twelve years old and had an exceptional talent for solving puzzles. Kacper, who was eleven, always cheered her on, although he was only brave when he was with his sister. On that cloudy afternoon, they both sat at a desk under the very model of a Saturn V rocket. Posters of space stations and planets glittered on the walls, and a real flight computer from a decommissioned research vessel blinked in the corner. Susie was just finishing putting together a sketch of her new computer game when they heard a quiet crack. They looked at each other in surprise. The ship's computer had suddenly switched on, even though no one had run it for years. The screen flashed with a strange light and the letters on the monitor began to pulse: "CAPTAIN ZUZIA - ARE YOU READY?" They both froze. Kacper's eyes bulged all the way out. - Zuzia, I think it's for you - he whispered. - But I... I didn't press anything! A map of the universe appeared on the monitor, with a point that flashed red. Underneath it was a string of characters: 'DANGER TO EARTH. ONLY YOU CAN READ THE CODE. DECRYPT AND COME TO THE STAR SHELTER. TIME: 10 MINUTES." Susie swallowed her saliva. Her hands trembled as she typed the first letters of the puzzling code. At the same moment, the lights in the lab went out, and the sound of slow footsteps came to them from the corner of the room....