It is 1944. Western Ukraine is occupied by the Nazi army. A large-scale, highly classified construction is under way. An order has arrived from the Soviet center of operations to find out what the Nazi's mission is. The Soviet High Command is concerned that the construction site runs through the line of the Soviet offensive.

A reconnaissance unit is deployed in order to obtain and transmit the information about the construction project. Additionally, a scout (a Soviet resident with an exemplary track record in cover operations) is placed behind enemy's lines. His task is to infiltrate the enemy.

The mission must be accomplished – be it by the reconnaissance unit or the undercover agent. There is no third option.