The life of Pavla Brus, a middle-aged, modest but principled woman, suddenly changes with a crush on a drilling foreman. Unable to restrain her feelings, she decides to cheat on her husband, divorce and leave the family. But her youngest son Kuzma, a teenager with an intelligent and piercing look at the world around him, stops her from a rash act, which is shaped by observation of Siberian nature. A philosophical attitude towards banal life processes allows the mother to reconsider her feelings for her husband Tikhon and the failed lover Nikolai.