Pola was seven years old and lived on the planet Zielonix together with her best friend, the little robot Robus. Zielonix was full of colourful plants that glowed in the dark, and the sky was always sparkling with purple clouds. On that day, Pola and Robuś were playing in the garden when suddenly a quiet, strange sound came from a bush with blue stars: 'Bzzzt! Click! Bzzzt!" Robuś moved his antenna and asked: "Pola, do you hear what I hear?" Pola nodded and looked behind the bush. There was nothing there, but the sound got louder! "Maybe it's a space slug?" - whispered Pola. Robuś lit up his eyes and they slowly approached the bush. Suddenly, a blue light shimmered from behind the leaves and something began to move.... What could it be?