When his daughter Anya commits suicide after being seduced by a man whose identity she refuses to divulge, Russian chemist Boris Karlov vows to avenge her. Because she was holding the famous Petroff necklace, the Drums of Jeopardy, at the time of her death, Boris assumes that her lover was a member of the aristocratic family. The legend surrounding the necklace states that if one of the drums is detached and sent to a man, he will die within twenty-four hours. Unaware that Gregor Petroff was Anya's seducer, Boris plans to kill the entire Petroff family, sending each intended victim one of the four drums to announce his impending death. After Boris, who has become a prominent Bolshevist, kills General Petroff, the remaining three, Prince Ivan, Nicholas and Gregor travel to America to enlist the aid of secret service agent Martin Kent. Boris follows them and kills Ivan. Meanwhile, Nicholas and Gregor have taken refuge in an apartment that art student Kitty Conover shares with her aunt Abbie. On Kent's advice, the brothers hide out in Aunt Abbie's secluded New Jersey home. Boris follows them and captures Gregor, who offers to tell him the name of his daughter's seducer if he can go free. He blames Nicholas, even though he himself is guilty. His lie does not save his life, however as Boris kills him with poison gas. Realizing that Nicholas and Kitty have fallen in love, Boris plans to avenge the death of his daughter by forcing Nicholas to kill his beloved. Nicholas and Kitty are about to drown together in the cellar where Boris has imprisoned them when the police arrive with Kent. Boris makes one last attempt to kill them all, but Aunt Abbie sends him to his death and he drowns in his own trap. Free from persecution, Kitty and Nicholas kiss.