Autumn 1941. German troops are advancing towards Moscow.
Petr Strelchenko (Alexander Gorbatov), together with military engineer Boris Zhikharev (Yegor Koreshkov), are going to blow up a strategically important dam for the enemy during a battle with the Germans. But the attempt fails. Saving Peter's life, Boris at the last moment does not dare to press the lever and, as a result, is in captivity. Strelchenko gets to his own people and soon meets Boris's wife, Vera (Vera Panfilova). He falls in love with a lively Komsomol member at first sight.
But news reaches Vera that Boris is now considered a traitor to the Motherland. He allegedly voluntarily surrendered and now works for the Germans.
The girl does not believe in her husband's betrayal. She sends her little son along with his mother (Evgeny Dmitriev) to evacuation and remains to wait for the city to be captured by German troops. Alone, Vera moves to the German rear. Through the occupied lands, hunger, pain and death, she goes in search of Boris. On the way, the girl joins the partisan detachment of the former entourage of Colonel Naletov (Mikhail Porechenkov). They are later joined by scouts under the command of Strelchenko, who is in love with Vera. They all have a common goal - to blow up that same dam.
However, during the operation, instead of proving Boris's innocence, Vera is suddenly personally convinced of his betrayal. And then she decides to execute her husband with her own hands ...