The film begins with the launching of a rocket. Credits roll far away.1985, there have been attempts to irrigate the Gobi desert. They find an extraterrestrial material. Somebody remembers that in Siberia, in 1008 there was an explosion with the power of an hydrogen bomb. At the beginning, they thought it was a meteor which had fallen to our planet, but 77 years later, they investigate the site. There is a new world federation for the investigation of space, and a space station is establishes on the Moon.Harringway Hawling (Oldrich Lukes), an atom-physicist, thinks that the material was the remains of an alien ship which exploded when entering out atmosphere. He makes his theories public.A computer tries to translate the alien language. Hawling thinks that the alien ship must have come from Venus, the morning star. They think they have identified some utterances, the first coming from another planet. Professor Sikarna (Kurt Rackelmann) wants all radio stations to focus on the message to Venus. Dr Tchen Yu (Tang Hua-Ta) wonders why such a technologically advanced society cannot be bothered to communicate more clearly with Earth's societies. Immediately, all radio stations try to communicate with Venus.They tell people living in Lunar III, the space station on the surface of the Moon. Hawling wants to send a spaceship to Venus; the idea makes journalists go wild. He is confident that the linguists will make them communicate.They launch a rocket. A female journalist (Lucyna Winnicka) describes the future astronauts. They will take with them a wheeled robot which is treated like a dog.Sumiko Oginura MD (Yôko Tani) doesn't want her old relationship with another crew member called Robert (Günther Simon) to bother or damage the mission. Astronauts will be put into hypersleep the duration of the journey. Robert, who is the pilot of the ship, has not really got over that old relationship. The CommanderThe astronauts are waved goodbye as heroes. The astronauts seem to be wearing body-size condoms as space-protective clothing.They make experiments while travelling. There is a Polish engineer, Professor Saltyk, (Ignacy Machowski), Commander Harringway checks on everything and comments about the media swarm. Professor Orloff (Michail N. Postnikow) is a chess enthusiast, but the robot Monaka defeats him.Soon things go hectic inside the ship. Talua (Julius Ongewe) is hurt when the spaceship goes through debris. The Commander that they have to stop to a halt - if they keep on accelerating like that, the ship will be destroyed.an astronaut has to go outside and mend the engine. Everything seems to be all right.They don't have radio contact with Earth, but they are late to their destination. Sumiko tries to make everybody it. The Polish engineer gets defeated once and again by the robot.All the crew, together with astronaut Raimund Brinkmann (Horst Schäfer) receive more messages from Venus. They say that it was a secret communication that they have deciphered without the aliens thinking they could, as they say that humanity is weak and not very clever, so that our planet will be invaded soon and all humanity will be exterminated and erased. The crew decides not to panic about it, and they will try to communicate with the aliens to say that they want peace. They can't talk with Earth to warn them either. There a suggestion of returning earlier, by all the crew decides to go on with their mission in spite of the danger.They have a meeting, as they can only land and take off once. They enter Venus and prepare the walk on Venus with a small helicopter. Immediately, they lose radio contact, probably because they are being blocked out. He goes through heavy clouds. The planet has an eerie atmosphere. The spaceship tries to go down as much as they can to rescue Brinkmann, who puts the robots into use by exploring Venus. The land it's a bit radioactive.Brinkmann finds some jumping technological insects, and puts in his bag one of them. The spaceship finally lands on Venus. Brinkmann sees the spaceship but he's attacked by a group of the Venus insects, so he can't call for his crew's help. The robot finds the crew and they are reunited. They investigate some petrified things. That forest is the origin of energy - maybe the alien race who wanted to finish off humanity couldn't agree. Finally, they find like torches and light.They have to go back because there are fumes everywhere and a kind of blob is flowing menacingly towards them. It traps Sumiko, but Robert rescues her.They get to the spaceship, which is about to leave. Herringway and the rest of astronauts can't talk to Talua because of the radio problems. In an abandoned cave outside the town, they find the shadows of scarred aliens which died in an atomic explosion. In spite of the storm, the Chinese linguist thinks that there has to exist life in the planet. The aliens wanted to invade Earth with atomic weaponry, but something went wrong and it killed them instead of Earth. They think that the fallen meteor must have been the beginning of the invasion. But Earth, without knowing it, started a chain reaction above an atomic warehouse, unknowingly.To leave Venus, they play around with Einstein's ideas, changing speed and energy onto mass and vice versa. Robert has to stay in Venus, just when Sumiko realises that the insect is growing, which proves that there's still life in Venus. Robert dizzily overhears that, being left in the planet.Finally, Robert can communicate with Sumiko, who wants to go back for him. Robert is walking around in his spacesuit. He shouts because he doesn't want to be left behind.However, the spaceship has to go on. They come back to Earth and everybody is waiting for them. They leave the spaceship and they explain that they have learned a lot, but that they paid a huge price. The Commander says that the expedition was a disaster, that Robert won't be forgotten, and that the alien race died because of their own fault. The Commander kisses his wife (Danuta Szaflarska), who was waiting for him.
Output: Question: Who accidentally triggers the weapon?, Answer: One of the scientist.