Responding to an early morning call reporting a family dispute, Officer Jim Street and his partner fall prey to an ambush by three gunmen. It is just one in a series of ambushes which have plagued the police. In the aftermath of the shooting Street's partner is dead, and Jim tries out for an opening in a newly formed S.W.A.T. unit being headed by Lt. "Hondo" Harrelson. The team's first assignment is to find and stop the gunmen who have declared war on the city's police.