The TV series "Tonkaya gran" tells the story of an unusual love triangle in a local prosecutor's office. A new employee, Pavel Kruglyakov, is transferred to the institution - a polite and charming man. However, his colleagues initially do not accept him into their circle, and the hero has to prove his "qualifications". When he easily solves two "unsolved cases" and saves his beautiful colleague Marina Sinitsyna, she starts paying attention to him. But her longtime admirer Martynov is not happy about this romance. He decides to do something despicable.