A group of scientists is sent to the planet Arkanar to help the local civilization, which is in the Medieval phase of its own history, to find the right path to progress. Their task is a difficult one: they cannot interfere violently and in no case can they kill. The scientist Rumata tries to save the local intellectuals from their punishment and cannot avoid taking a position.
The film is based on the true story of Captain Marinesku and set in 1944 during WWII at the Russian Navy Base. Young and beautiful Tanka is in love with Aleksandr Marinin, the brave Captain of the Russian submarine. He is under the KGB surveillance, and his life is at risk. He takes his boat to fight the Nazi fleet, and he cannot come back home without a victory.
A fat middle-aged man in German officer's uniform gets off a train somewhere in Russia in winter. He is a doctor who has just been called up we learn eventually. This is the end of the line- the Germans are about to retreat. He goes to a hospital which is being evacuated and is thrown out. Kicked out he wanders with another conscript- a failed actor turned postman. The postman is deafened by a shell explosion. They meet their Russian equivalents, others as bad at killing as they are, while other Russians and Germans kill one another around them.
