Lookridge, crime connoisseur, and Estabrooks, investigator in the field of hypnosis, combine their specialities in a novel of espionage involving a new -- and inexplicable -- secret weapon. A series of treasonable acts among army and navy officers of high standing puts Johnny Evans, Intelligence, and Madeleine, whom he loves, on the trail which begins with the body of a German psychologist found aboard a sunken American submarine. Proceeding to America, he finds Madeleine involved with the enemy, confused and confusing in her actions, and he suspects that only hypnosis can have alienated her. Evans is drugged, made the victim of an attempt at hypnosis, escapes, and finally through Madeleine, able to identify the men as well as the method and put an end to it. The scientific slant is an added attraction for a sustained story of undercover warfare. The Lookridge name should add a substantial number of crime addicts.