The Operational Search Team of the Counterintelligence Department of the Front, led by Captain Alekhin, is searching for a sabotage unit codenamed "Neman". The group of saboteurs is led by the Nazi spy Mishchenko, whom Alekhin knows well. Mishchenko is responsible for gathering secret information that the Nazi leadership needs to determine the further actions of the Soviet troops. Alekhin and his colleagues work through numerous scenarios, but Mishchenko always manages to slip away...