Adam-12 is a television police drama that followed two police officers of the Los Angeles Police Department, Pete Malloy and Jim Reed, as they patrolled the streets of Los Angeles in their patrol unit, 1-Adam-12.

A woman walks into a police station with a pistol and a vial of nitroglycerin. It turns out that she is the widow of an infamous criminal shot and killed by a detective. She notifies the police that she is waiting for the detective who shot her husband and intends to kill him in front of his fellow officers.