In Moscow, under mysterious circumstances, a young policeman is killed. The witness of the murder is his girlfriend Lera Nemchinova. The case is transferred to Petrovka. Gordeev's bosses insist on considering the version of the possible connection of cadets with criminal structures. Kamenskaya simultaneously begins to develop her own version. The fact is that Lera is the daughter of a famous composer who died ten years ago. Nemchinov was shot at his own dacha, and his father, Grandpa Lera, confessed to the murder. After serving his sentence, Nemchinov the elder returned to Moscow and now lives with his granddaughter. Kamenskaya meets Lera. On the girl's hand, she sees a ring that took place in the case of the murder of a high-ranking official's wife. The murder, committed several years ago, was never solved, and no one else saw an expensive piece of jewelry.