The operative-search group of the Front Counterintelligence Directorate under the leadership of Captain Alekhine searches for a sabotage group codenamed "Neman". The group of saboteurs is led by German agent Mishchenko, who is well known to Alekhine, and whose task is to collect the intelligence necessary for the German command to determine the direction of the Soviet army's main strike. Alekhine and his group, in the course of an extensive search, work out one version after another, but each time Mishchenko manages to escape.
