Graduate students in the Historical Museum find a diary dated 1919. In the diary, the author confesses to the murder of five people. The terrible deeds of the past are the key to unraveling a number of crimes committed in our day.

Graduate students have a party in the archives of the Historical Museum, where they randomly find a diary dated 1919. The diary instantly arouses interest, because the author from the first lines confesses to the murder of five people. Heroes do not realize what role this find will play in their life - The terrible deeds of the past are the key to unraveling a whole series of crimes committed in our day.