Under strange circumstances, bank security guard Alexey Rakitin dies. An implant of unknown purpose exploded in his ear. There is no information about the device in the medical record, and the man's hearing was fine. Rakitin's girlfriend claims that Alexey did not know that he had an implant installed. But how can this be?..

In a hotel room, judge Valery Kulish was strangled with women's tights. It turns out that at the time of the murder there was a blackout in the hotel. Suspicion falls on the prostitute Angela Ponomareva, who served Kulish, and the visiting businessman Roman Rozhkov, who started a brawl in the bar. But Kulish's wife points to electrician Lukyanov, who previously threatened to kill her husband...

Early in the morning, IT company employee Irina Nikulina was killed in her own car. In the back seat they find the murder weapon - a pistol registered in the name of her husband Alexei. The man is detained, but he denies involvement in the murder. The conclusion of the examination of the traces left in the car will shock the operatives - at the time of Irina's murder, Kuzmin was in the next seat...