On the way home with his family, Danny hits a man with his car who is fleeing a masked gunman and the boys and Linda are left caught in the crossfire. Though unharmed, Jack struggles to deal with the shooting, and Linda is furious with Danny's reckless conviction to his job even while off duty. Danny is surprised to find out the "victim" he hit is actually a convicted child molester living in a nearby halfway house. Despite Linda's disapproval, Danny and Jackie fervently track down the gunman and realize he's one of Danny's neighbors, an impulsive man who was seeking vengeance on another convict who had robbed his daughter also living at the halfway house. Meanwhile, Frank begins seeing a psychiatrist to deal with the impending death of an old comrade, a first responder injured on 9/11.