St. Petersburg. Winter of 1917, the eve of the February Revolution. The maid finds in the room the corpse of the murdered tenant. In his pocket, a hotel account was found in the name of Karl Fischer, a well-known banker. An investigation is beginning. In the list of suspects - an agent of the secret police...

The Key

A story about the fate of several generations of an old Moscow family. The life of these people, full of drama, fatally intersects with the historical fate of Russia. The plot focuses on the love of a young officer and a girl against the background of Stalinist socialism.