Undercover cop John Franklin infiltrates a crime syndicate being run by the incarcerated mob boss Rocky Thorpe. Thorpe conducts his business via a short-wave radio concealed in his cell. One day before his scheduled release Thorpe is placed in solitary confinement and Franklin, Thorpe's physical double, takes his place. Soon changes in the gang's activities are subtly made. As Thorpe, Franklin orders the mob to keep careful records of their activities, to gather enough evidence to convict them all. Trouble ensues when Rocky escapes from jail.—Robert