Guy Garrick, a detective who has made a scientific study of crime, has been the hero of a number of earlier short stories. In the present novel he is engaged in tracking down a gang of motor bandits. "An expensive car has been stolen from New York, and one of the stool pigeons of the police has been mysteriously murdered with no trace of the bullet or weapon that killed her. The body is found in New Jersey, though the police believe that she must have been murdered in a ladies' pool room, which she was investigating. The police, the city detectives, the automobile detectives and Guy Garrick are all working on the problem, and the unravelling and subsequent glory of Garrick are very exciting."