The action takes place in the summer of the early 1940s in the Soviet Union. The authorities of the country learn about the increased activity of Nazi physicists in creating atomic weapons. The Soviet authorities want to seize the developments of this new type of weapon, which can have a significant impact on the course of the war and even change history. Spy Franz Hartmann, who works undercover in Berlin, must carry out a complex and multi-step operation to obtain the schematics. The head of German intelligence, Walter Schellenberg, is also involved in his mission.