The series centers on Rodion Meglin (
Konstantin Khabensky), a highest level investigator of the Russian police who is also a sanctioned
vigilante, hunting down the criminally insane ("maniacs" in Russian) who slip through the cracks of an ill-suited justice system. He's used to working alone, never revealing the secrets of his method. A young law school graduate, Esenia Steklova (
Paulina Andreeva), is assigned to the department of the
Investigative Committee where Meglin serves, becoming his trainee. Esenia has personal motives for working with the famous investigator - her mother was killed under mysterious circumstances, while her father hides key details of what happened. She's given up hope of finding the murderer, but wants to learn as much as she can from the seasoned investigator. Throughout the series, Esenia encounters unexpected challenges working with Meglin. ==Cast==