In 1939, Major Ivan Rosly, at the behest of ill-wishers, finds himself in the thick of the Soviet-Finnish War. But it is his unit that breaks through the impregnable Mannerheim Line, which becomes the most important stage of the future victory. In spite of everyone, Rosly returns from that war as a Hero of the Soviet Union with the rank of colonel. At the beginning of the Great Patriotic War, he is surrounded, but leads thousands of Soviet soldiers to their own.

1941年秋，德军逼近莫斯科，苏联军队奋勇抵抗。严冬来临，前线形势依然十分严峻。希特勒此时决定给苏军致命一击：刺杀斯大林。而苏联国家安全部也对此有所察觉，为了斯大林的安全，大尉别烈日诺立刻带领自己的行动组展开调查。毫无疑问，敌人就潜伏在周围。而此时，一个神秘女人波琳娜突然闯入了别烈日诺的生活。他们之间会发生什么纠葛？行动组会遇到怎样的挑战？谁才是真正的间谍？