Precinct 21 receive a new rookie on the squad probationary Patrolman Paul Cochran. His first assignment is to guard a prisoner named John Wigan who is in the New York Hospital after being shot by a policeman while attempting an armed robbery on a liquor store. Patrolman Cochran is told by his Captain to do everything by the book, which he does, even to the point of not allowing an FBI officer to talk to the prisoner.