Olga Lavrentieva suffers because her fiancé Stas left her and married her best friend Svetlana. Olga constantly calls the happy spouses, goes to visit them, and they feel sorry for her, although they are tired of her visits. And suddenly Svetlana is attacked with a knife, almost killing her. Olga is accused of the assassination attempt. True, Lavrentieva is released very quickly - there is no evidence against her. But Stas is sure: she is the criminal, his wife has no more enemies. Stas begins an independent investigation. Anger and despair are intensified by the fact that his beloved Svetlana suddenly begins to behave coldly and aloofly towards him...