Following a training exercise with S.W.A.T. officers from another division, Hondo and Street find the dead body of officer Frank Crane with the words "Kill S.W.A.T." pinned to his chest. The murder of Crane is the forerunner of a series of attempts to wipe out S.W.A.T. by brothers Mike and Simon Bishop and their fanatic sister-in-law, Joanna, who is convinced that the death of her husband was the result of S.W.A.T. "brutality."