Everybody dance, or Kashchei from Bersenevka

Yana and Margosha decide to urgently lose weight and enroll in the Zulfiya dance school. In the classroom, they meet a charming girl named Milena. Suddenly Milena falls to the floor and dies ... It turns out that Milena was poisoned with a rare poison used by the special services. The threads pulled by the independent detectives brought them to the famous "House on the Embankment". A web of intrigue and crime, treachery and greed, family heirlooms in the "local diamond fund", the history of the ancient noble family of Klansky, murders, chases, and, finally, the inevitability of punishment for the evil inflicted - this is the result of the investigation of two tireless friends - Yana and Margosha.