Retired Major Cherkasov helps former colleagues at MOORE to investigate the murders of lottery participants who won a large sum of money. Kovalev and Timofeeva believe that the organizer of the prank, Belousov, and the presenter, Shorokhov, are behind the murders. Gradually unwinding the case, MOORE's staff is facing resistance from officials for whom the lottery is an important budget item. Unexpectedly, the investigation leads the Murovites to the Research Institute of Mathematics and Cybernetics, where a group of young scientists is conducting research aimed at studying and optimizing ways to earn money through the state lottery.