Childhood friends Rocky Barnes and Dan Purvis are Los Angeles prowl car cops on night duty.

Both men are attracted to radio communicator Kate Mallory but she is reluctant to get involved with policemen, her cop father having been killed in the line of duty.

While Barnes and Purvis are shown patrolling the streets and responding to crime small and organized, it is their arrest of murderous racketeer Ritchie Garris that is most consequential.

After his arrest Garris swears vengeance on the duo, and quickly carries out his threat by escaping from prison, and shooting Barnes in the face several times.

After months of hiding from the police, Garris finally believes it is safe to collect to his girlfriend Terry Romaine and then flee to Mexico.