The film is set in post-World War II Moscow. Lieutenant Vladimir Sharapov (Vladimir Konkin) is a young reconnaissance officer and a decorated war veteran who has just returned from the war and is assigned to peacetime service with the famous MUR (Moscow Department of Criminal Investigations). There he becomes part of an elite detective team led by the brilliant, tough, no-nonsense Captain Gleb Zheglov (Vladimir Vysotsky). The duo becomes embroiled in two seemingly unrelated investigations: that of the murder of young aspiring actress Larisa Gruzdeva, and the hunt for a brazen, vicious gang of armed robbers that calls itself "The Black Cat" and constantly manages to evade capture.