According to the story of the same name by Yulian Semyonov. Employees of the Moscow Criminal Investigation Department - Colonel Alexei Pavlovich Sadchikov, Major Vladislav Nikolaevich Kostenko and Senior Lieutenant Valentin Roslyakov are investigating the impudent robberies carried out by a group wearing dark glasses criminals. The City Savings Bank was robbed. The investigation of the crime indicated the involvement of a teenager, who soon came to the criminal investigation himself. With his help, the robbers who were preparing the next raid were caught. But the most dangerous criminal — "Prokhor" — is still free....