An elite police squad tracks a volatile killer through the streets of Los Angeles in this urban thriller featuring Keith David. They are our first line of defense against the most dangerous criminals in the city. If they do their job right, the average citizen never knows that they even exist. But now, a murderous psychopath is on the loose, and in order to stop him the S.I.S. will have to use every trick in the book to catch a killer, and maintain a low-profile.