Events find heroes on the eve of the Great Patriotic War. Irina (Maria Mashkova) is the wife of a high-ranking person, chief engineer of the People's Commissariat of the USSR Electrical Industry Grigory Voskresensky (Alexander Makogon) and the daughter of an enemy of the people.

She teaches German at Moscow State University, and NKVD Major Pavel Nechai (Pavel Trubiner) turns to her as a specialist in ancient Germanic epos. He asks Irina for help in finding a rare German book, the text of which is used for enemy encryption.

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A sabotage group operates in the city, and Irina is drawn into a large-scale espionage story. And not only her. Her husband and childhood friend Andrei Galkin (Anton Feoktistov), ​​who suddenly returned to her life, with whom she was passionately in love in her youth - they also find themselves in the field of view of the People's Commissariat of Internal Affairs.

War breaks into the lives of heroes and rips off all masks. And everyone has to make their choice between fear and courage, betrayal and honor, hatred and love ...