Operation Holtsauga was a Nazi plan to destroy Soviet ships and aircraft approaching Murmansk, which was carried out in 1942. Near Bezymyanny Island, a Soviet ship struck a mine and sank, and engineer Okulich, who miraculously survived, was taken prisoner. However, he managed to escape and even took German officer Ritter with him. During a week of difficult travel to the mainland, he learns from the German about the Holzaug plan. Thirty years later, an explosion occurs on Bezymyanny Island during the construction of an astrophysical station. Now Okulich must uncover all the details of the old operation in Munich...