A prisoner (played by Sal Mineo) is broken out of the prison ward of County General Hospital. His name is Joey Hopper, and his followers are called the Hopper Family; they consist of alienated youths who view Hopper as their spiritual leader. All escape routes out of the city have been closed, and S.W.A.T.'s job is to conduct a sweep of the city and find them. Hopper's goal is to exact revenge against all those who prosecuted him... including "Hondo" Harrelson.