Engineer Los undertakes the construction of a machine destined to go to planet Mars. He has enough with the Earth where he has conjugal disappointments and many other problems.
One day, after the continuation of a quarrel with his wife, he shoots at her and decides to escape immediately to the planet Mars on board his machine. He'll be accompanied on his trip by a demobilized soldier of the Red Army, Gussev, who wants to export his revolutionary ideas to Mars, and by a detective tracking him for his woman's murder.
When he arrives on Mars, Los falls in love with the sovereign of the planet, Aelita. Because of the Prime Minister, they are imprisoned in cellars with slaves. With the help of a server of Aelita, they succeed in escaping and pushes the slaves to revolt against their oppression. While the uprising is on the verge of winning with the party, Aelita betrays them...
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In rage, Los wakes up in the station of Moscow where he stayed while escaping the detective at the beginning of the movie : it was only a dream. He then returns home to find his wife, in perfect health, who in fact, did not betray him. He abandons his fanciful projects and decides to remain on Earth after burning his drawings.