Olive, Maks and Antek were looking forward to their summer holidays, but even they did not expect an ordinary summer astronomy camp to turn into something completely unusual. In the evening they set up the telescope in a clearing, far from the city lights. It was quiet, only the crickets were chirping. Maks adjusted the eyepiece and began to observe the distant stars. "See this!" - he called out suddenly. In the depths of the sky, a point was shining, blinking green and red. It wasn't an aeroplane or a satellite - it was behaving very differently. Antek, always the first to experiment, tried to pick up a radio signal from that direction. There was silence in his headphones for a moment, then he heard a strange, repetitive rhythm: three long beeps, one short one, a pause, then three long beeps again. "It must be some kind of code!" - whispered Olive, whose imagination immediately suggested the thought of a cosmic message. They spent the rest of the night trying to unravel what the puzzling signal meant. In the end, they decided to send their own answer into unknown space. As they pressed the send button, they felt as if the fun was turning into something really serious. The next night, the sky above the clearing lit up with a greenish glow. Amidst the darkness, a strange shape appeared and got closer and closer. The three friends, with a mixture of excitement and fear, watched as something they had never seen before landed before their eyes, and their radio station began to receive a new, even more puzzling message....