S.I.S. follows an elite, covert police squad as they stalk the worst of the worst on the gritty streets of Los Angeles. As an underground arm of the law, the offices of the Special Investigation Section fight the toughest crime with none of the glory. But when their dangerous methods come under close scrutiny, their very existence is threatened. With a notorious killer blasting his way across the city, the squad must use all their skills to bring him down in this explosive action thriller.