In Moscow, after the sudden death of her husband, Natalya Shakhovskaya is in mortal danger. Someone wants to kill her and makes an unsuccessful attempt on her life. Natalya remains alive. Lieutenant Polyansky is trying to investigate the attempted murder of the young Countess. His innate intuition tells him that the deaths of the old Count Shakhovsky and his son are somehow connected. He suspects that Anatole Dubovitsky is involved in the death of the Shakhovskys and in the attempt on the life of the young Countess. After all, Anatol is the heir to all Moscow real estate and the Yaroslavl estate of the Shakhovsky family. However, Anatole has a firm alibi at the time of the assassination attempt on Natalya. Lieutenant Polyansky suggests that Anatole has an accomplice. But nevertheless, for the sake of safety, the Lieutenant convinces the Countess to go to the Yaroslavl estate. However, a series of mysterious events unfolds there that completely change the life of the lieutenant.