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.
A Soviet cargo ship carrying medical opium gets attacked by pirates of an unknown nationality. The crew is left to die on a sinking ship but they manage to escape and now must fight the pirates for survival.
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".
