On her first day in the criminal investigation office Maria Krapivina finger-prints a recidivist thief called Buffet who was arrested during the attempted robbery of a jewelry store. During the interrogation Buffet attacks Masha and whispers to her that there’s a traitor in the police. The next day the criminals try to rescue Buffet during the prisoner transfer and Shvedov saves Masha’s life. It ends up with a burnt corpse of Buffet. But then Masha learns that it wasn’t him while doing a medical expertise …