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.

Lena returns to her home in a remote, war-ravaged Armenian village to try and persuade her grandparents to leave with her for safety in Moscow.

Military doctor General Klenski is arrested in Stalin's Russia in 1953 during an anti-Semitic political campaign accused of being a participant in so-called "doctors' plot".