Minister of Internal Affairs Plehve instructed Lykov to investigate the circumstances of the death of the scientist Mikhail Filippov, who in the summer of 1903 announced his invention - a new, unprecedented weapon, so destructive that wars with it would become pointless. The day after this news was published in the newspaper, the scientist was found dead. Doctors declared death from natural causes - the deceased had a heart condition. And soon counterintelligence intercepted a letter from the German resident with the message that Filippov had been killed, the authorities had no idea about anything, and the inventor’s papers were about to be sent to Berlin. How lucky will Lykov be this time? Will he be able to find the killers of the inventor of the “death rays”? Will he be able to stay alive?..