Police Major Andrei Klotov is investigating the death of a nanny who worked in the mansion of businessman Oleg Kolosov. An elderly woman died after falling down the stairs. A high dose of sleeping pills was found in her blood. The major moved into Oleg's house under the guise of a business partner. Within a day, the detective realized that there was every reason to suspect numerous members of Kolosov’s household of criminal conspiracy. A few days later, the mansion’s guard, Vadim, dies under mysterious circumstances. Next to the corpse, the major discovers a piece of paper with the inscription “Queen of Hearts”...