Plot synopsis: 1944. According to information obtained from a recruited German agent, a major act of sabotage is being planned in the Murmansk port, through which the USSR receives vital military cargo from the allies along the northern route. Counterintelligence officers Sergey Saburov and Elena Soley have a new dangerous mission, to prevent large-scale sabotage in the Murmansk seaport, find and neutralize the enemy.