NOTE: All citations in this Study Guide refer to the Kindle edition of End of Watch, published June 2016.

In this final novel in the Bill Hodges Trilogy, End of Watch by Stephen King, Bill Hodges and his friends are in a battle against death and disbelief. With the aid of an experimental drug, Mercedes Killer Brady Hartsfield has gained the ability to inhabit the minds and bodies of his doctor and the hospital librarian. Using these two as both vehicles and slaves, Brady sets off a suicide epidemic among those who attended the ’Round Here concert at which he had intended to detonate a bomb, killing himself and other attendees. Hodges hurries to solve the case as he tries to come to grips with his own diagnosis of pancreatic cancer.

End of Watch begins with a flashback to the April 2009 Mercedes Killings at the City Center. The memories are those of Rob Martin and Jason Raspis, the ambulance crew first on the scene of the tragedy. They were in charge of transporting Martine Stover, one of the most severely injured of the victims, to the hospital. Martine survived but was paralyzed from the chest down.

In the next section, the story picks up nearly seven years later. Hodges and his friend Holly Gibney are called in to consult on a case that appears to be a murder/suicide. It appears that Janice Ellerton gave her daughter, Martine Stover, an overdose of pain medicine and then suffocated herself. Pete Huntley, Hodges’ old partner calls Hodges in because the case is related to the Mercedes Killings. It is obvious that Pete’s new partner, Izzy Jaynes, does not want Hodges and Holly involved. Holly believes it is because Izzy knows that Holly and Hodges will look further into the strange deaths than Izzy wants to do.

Hodges and Holly not only discover a large “Z” written on the counter in the bathroom where Janice killed herself, but they also find a Zappit, an obsolete game console, tucked in Janice’s chair. Janice’s housekeeper gives them a strange story about a man who gave Janice the console as a gift. Hodges also finds evidence that a house for sale across the street from the Ellerton-Stover house was being used as a place to spy on the two women. A “Z” is found on a door post in the garage, which had been broken into.

Meanwhile, the reader learns that Brady Hartsfield has learned he not only can move things with the power of his mind, but he can also enter the minds of people once they are in a state of hypnosis. This mind control allows him to use a person like a vehicle in which his own mind and consciousness can drive. Brady first takes over the mind of Library Al, the hospital worker who gave him a Zappit, a game console donated to the hospital because the company went bankrupt. In order to take control of other people, Brady comes up with a way to amp up the already hypnotic effect of the Fishin’ Hole demo that is loaded on each of these devices.

Brady next blackmails and manipulates his neurosurgeon, Dr. Felix Babineau, into becoming one of his minions. It is Dr. Babineau, in his alter ego as Dr. Z, who not only hands out Zappits, but also arranges for Brady to purchase Zappits in bulk so he can use them to control to minds of those who had attended the ’Round Here concert he had intended to disrupt with a bomb years before. Brady hopes to set off a suicide epidemic.

Freddi Linklatter, Brady’s former co-worker at Discount Electronix, becomes Brady’s unwitting partner in crime after she visits Brady one day. Knowing she needs money, Brady hires her through Dr. Z to reprogram the Zappits and set up a repeater that can send out messages and reprogramming information to all of the Zappits. He has arranged to give out these Zappits as fake consolation gifts for those who were not able to enjoy the concert.

Hodges and his partner Holly are reunited with Jerome, working as a volunteer for Habitat for Humanity, to stop Brady before he can persuade unwitting teens to end their lives by suicide. Just as Hodges is about to fall prey to Brady’s mind control, a text alert startles both men and helps to turn the tables on Brady.