In attempting to develop a chemical which would make a person super-intelligent, Dr. Montrose fails and the subjects of his experiments metamorphose into hideous monsters who band together and prey on humans. With the police stymied, a young detective attempts to track down the leader of the group of killers, known only to have a small crimson stain in one eye.

Ever since Henry Falkins had caused Newt Spooner to be sentenced to prison, Newt has nursed a red-hot hatred for him and a desire to see Henry dead. That is until he meets and falls in love with Minerva Rawlins who makes him reevaluate his obsession. When fate throws the two men together in the Philippines during wartime and the opportunity to slay Henry occurs Newt realizes that he has resolved his inner torment. He returns to Minerva a man at peace with himself.