November 1824. Catastrophic flood in St. Petersburg. Emperor Alexander Pavlovich, consumed by guilt for the murder of his father, conceives a plan to secretly leave the throne and go into private life. In this he is helped by his faithful adjutant, Prince Repnin. Having lost his beloved during a flood, Repnin seeks the meaning of life in serving the Tsar and the Fatherland. A heavy blow comes to him when he learns that his fighting friend Shevaldin is a member of a secret society plotting to overthrow the monarchy. Former comrades find themselves on opposite sides of the barricades. But at a difficult moment, when Repnin has to defend the sovereign from assassins, Shevaldin, without hesitation, comes to the aid of his friend.