Mid 80s, Moscow. Vladimir Chayanov, the senior detective of the MUR, is appointed head of the investigation team in one high-profile case - he is the best, so no matter how he investigates the murder of the Loshkarev family. The bodies of the father, his elderly mother and eldest son were found in their own apartment in Moscow. The youngest son survived - he practically did not see anything, because he hid in the sofa, and the mother of the family, who was not at home at that moment. A large amount of money is found in the sofa where the boy was hiding, but how can an ordinary family, whose head worked as a simple driver, have so much money? Elena Kozina is sent as an assistant to Chayanov: she is an operative worker who was transferred to an internship at the MUR from Leningrad. Chayanov believes that this operational work is not for gentle girls, so Lena fills up with paperwork. But she, having studied the case materials and taking advantage of Vladimir's absence, begins her own investigation.
