Lost Signal from Proxima Beta

In the town of Goats on the outskirts of space station Earth III lived three friends: Lena, Kajtek and the robot Maks. They spent every day inventing new ideas and experimenting in the old observatory outside the town, where, among the cobwebs and dusty telescopes, they talked about life on other planets. One evening, as the station's lights illuminated the great domes, Lena accidentally set the radio wave receiver to a frequency that had never sent any sound before. Suddenly there was a quiet, rhythmic crackle - as if someone was sending a walrus-coded message. Kajtek approached with a baked look on his face. "It must be a signal from space! Maybe from Proxima Beta? I heard there are strange creatures living there..." The robot Maks began to process the signal with his artificial senses. A sudden noise came from the speaker, and after a moment a string of glowing characters appeared on the screen: "COME...WE NEED HELP...WE ARE NOT ALONE...". The friends looked at each other in disbelief. Was someone out there, in a distant corner of the galaxy, really calling them? There was silence outside the observatory door, and the starry sky stretched beyond the windows. Lena reached for the planetary atlas, Kajtek pulled out his self-built computer, and Maks had already started calculating the course to Proxima Beta. Suddenly, the receiver screen flashed and an additional signal pierced the darkness in the room - this time shorter, sharper, like an alarm. And then they heard something else: a rustle, as if someone had stepped on the metal floor just outside the observatory entrance.... The friends held their breath. What was waiting behind the door? Was it someone who had sent a puzzling message? Or was it... something else entirely?