St. Petersburg, end of 1825. Senator Dvinov is found dead in a locked office. Who benefits from the death of a statesman? Political rivals? Family members? To the conspirators whose time is about to come? Yes, to almost everyone who knew him! The extravagant investigator Polikarpov will come to this conclusion as soon as he sets off on the trail of the killer. But...what does this have to do with the dead rat found in the deceased’s tureen?