Several major robberies take place in Leningrad and the region, but the criminal leaves no trace. The Inurkollegia announces that the administrator of the boarding house "Otdykh" Balyasin unexpectedly receives a large sum of money as an inheritance, and the police decide to set a trap for the criminal, believing that he will not pass by such money. An employee of the Criminal Investigation Department arrives at the boarding house, and it soon becomes clear that the elusive criminal is one of the vacationers at the boarding house.