The film opens at a station where a train is overdue. The waiting crowd is curious, and a group of soldiers among them sets off to find out what has happened. When the train is found, it is discovered to be empty save for a solitary sleeping passenger. The rest of the travellers and the crew have flocked to a nearby river, where army tanks have assembled. At this point the story begins, and the film looks back to events earlier in the day which led to this incident. A small boy, Aleko, swimming in the river with his two friends, is trapped by a falling stone. He is unable to move, the river is rising and his situation becomes perilous. It becomes urgent to do something to save him.

This parable expresses the importance of the individual in the sweep and march of society. In the script writer's own words, "If the fate of a single child can stop part of mankind, what should humanity do for the fate of the world?"