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.

Autumn, 1968. Nadia, a young woman with strict views on life, a methodologist at the regional House of Culture, goes to the cinema with her friend Sasha. The premiere of the film "Three Poplars on Ivy" took place in their city. Suddenly it turns out that there are no tickets, and you can only buy one with your hands.