A commuter train is violently derailed when it strikes an SUV parked on the tracks, resulting in 12 deaths, leaving Detectives Fontana and Falco sifting through massive debris, until they lock onto a depressed construction worker who maintains he only intended to commit suicide, not homicide. EADA McCoy cannot wait to get his hands on the case but his grip gets more slippery when the accused's attorney hints at an insanity defense, and the suspect later shocks everyone in court.