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.