Shane Scully and his partner are assigned to the case of "The Fingertip Killer" - serial murderer preying on homeless Vietnam veterans in Los Angeles. Every two weeks he strikes: he beats his victims, and then shoots them in the back of the head. Once they're dead, he cuts off their fingertips and tosses their bodies in the river. Into this explosive mix, comes another killing that Shane believes doesn't fit the pattern. Scully suspects an elaborate copycat murder. A bullet pulled from the last victim's skull produces what police call a "cold hit"- an unexpected ballistics match linking one unsolved case to another - and the previous victim was an LA Police officer, killed ten years earlier. After FBI agents throw him off the Fingertip Killer case, Scully teams up with his wife and boss, Alexa. Outside the law and deep undercover, they fight to see justice done for the slain officer, and, possibly, to unravel a murderous plot with criminal connections high up in the U.S. government.