1981. Cherkasov investigates a complicated case. And, as always, his superiors are dissatisfied with him. They reprimand him at meetings and threaten to remove him from his position. It is quite difficult for Cherkasov to imagine himself in retirement. But he understands that he has started to tire quickly and miss important information. In short, he is getting old. Then a young investigator appears who knows how to work with the new computers and brings a lie detector to the department. Ivan Petrovich decides to give in. But in his last case, he must put an end to it himself.