Brady Hartsfield drives a stolen Mercedes into a crowd at a City Center job fair, killing several people and leaving Martine Stover paralyzed.

Holly Gibney stops Brady from detonating a bomb at a concert by striking him repeatedly in the head, causing the brain damage that lands him in a clinic.

Hodges abandons a medical appointment and drives with Holly to investigate the apparent murder-suicide of City Center survivors Janice Ellerton and her daughter Martine.

Holly finds a Zappit game console and a letter Z drawn in marker on the bathroom countertop at the Ellerton crime scene.

Housekeeper Nancy Alderson tells Hodges that a stranger gave Janice a free Zappit at a grocery store just before her depression began.

Hodges's doctor confirms his stomach pains are pancreatic cancer, giving him roughly a year to live.

Brady, operating through Dr. Babineau, hypnotizes head nurse Ruth Scapelli with a Zappit and brings her fully under his control.

Barbara Robinson nearly steps in front of a moving truck while hypnotized by the hacked Fishin' Hole demo playing on a Zappit console.

A clinic duty nurse secretly meets Hodges at a bar and reveals that Dr. Babineau has been running illegal drug experiments on Brady, who can now move objects with his mind.

Brady shoots Freddi Linklatter, fully takes possession of Dr. Babineau's body, and then travels to the clinic to kill his own original body.

Freddi Linklatter confesses everything to Hodges, Holly, and Jerome about the Zappit scheme and Brady's possession of Babineau, and Jerome disconnects the signal repeater.

Jerome slips into a deep hypnotic trance while holding an infected Zappit, murmuring that he is watching his own beautiful funeral.

Brady ambushes Holly and Hodges near the hunting cabin, knocks Holly unconscious with a rifle butt, and forces Hodges to carry her inside.

Holly recovers consciousness and shoots Brady in the shoulder; Jerome arrives in a snowplow and crushes Brady under the blade.

Holly and Jerome meet at Hodges's graveside, where the headstone reads 'Kermit William Hodges, End of Watch.'

The story begins with Brady Hartsfield's original mass murder at City Center, the catastrophe that puts Martine Stover in a wheelchair and haunts every subsequent event. Six years later, Hodges and Holly are pulled back into Brady's orbit when they investigate a suspicious murder-suicide involving City Center survivors, and Holly's sharp eye uncovers the Zappit connection. The investigation accelerates even as Hodges quietly receives a devastating cancer diagnosis, and Brady's grip tightens through hacked consoles and mind-controlled proxies. A confrontation at Brady's remote hunting cabin puts both Holly and Hodges in mortal danger, and it is Holly and Jerome together who ultimately stop him. The book closes months later at Hodges's graveside, where the inscription on his headstone finally gives the novel's title its full meaning.

The main arc of Brady Hartsfield's return and final defeat.

Brady regains full consciousness in the brain injury clinic and begins testing newly emerging telekinetic powers on objects in his room.

Brady discovers he can enter and control nurse Sadie MacDonald's mind by exploiting the mental vulnerability caused by her petit mal seizures.

Hospital librarian Al Brooks gives Brady a Zappit console and unknowingly becomes Brady's first fully possessed agent, thereafter known as Z-Boy.

Brady recruits his former coworker Freddi Linklatter through Library Al to hack Zappit consoles and embed a mind-trap inside the Fishin' Hole demo.

Pete reveals to Hodges that two other City Center survivors, Keith Frias and Krista Countryman, previously died by suicide together.

Hodges searches an empty house across from the Ellerton home and finds a hidden surveillance post with a letter Z carved into the doorjamb.

Head nurse Ruth Scapelli is found dead by suicide, with the letter Z drawn in her own blood on the floor beside her body.

Brady, inhabiting Library Al's body, shoots Cora Babineau at her home and then transfers his consciousness into Dr. Babineau, leaving Al to take the blame.

Hodges visits Barbara's friend Dinah and learns that Zappits were distributed through a website called badconcert.com and that users were directed to a prize site called zeetheend.com.

Hodges stares at the Fishin' Hole demo on Dinah's Zappit and realizes with alarm that he has lost ten minutes without noticing.

Freddi Linklatter regains consciousness after being shot and discovers that a flask and an Altoid tin in her pocket deflected the bullet, leaving only a flesh wound.

Pete calls Hodges to announce that Brady's body has been found dead by apparent suicide and insists the case is finally over.

Brady activates the zeetheend.com suicide website, and a teenage girl throws herself from a window, landing in a snowbank and surviving.

Isabelle surrenders the Zappit suicide case to the state police, citing her promotion prospects and refusing to acknowledge any connection to Brady.

Hodges celebrates his 70th birthday in the hospital surrounded by Holly, Jerome, Barbara, and his daughter Allie, who has reconciled with him.

This pool traces the secondary layer of events that give Brady's plan its shape, from his early recovery in the clinic through the recruitment of Library Al, Freddi Linklatter, and an unwilling Dr. Babineau. Key moments include Brady eliminating witnesses and disposing of inconvenient people as his operation scales up, while Hodges and Holly uncover clues that the official investigation keeps ignoring. Institutional obstruction — especially Isabelle's relentless career calculus — repeatedly forces the case out of police hands and into Hodges and Holly's lap. A near-miss with Freddi's survival and the alarming activation of a mass-suicide website keep the pressure at a peak heading into the final act. The pool closes with Hodges's birthday gathering in the hospital, a quiet celebration shadowed by the knowledge that his end of watch is approaching.

The building blocks of Brady's scheme and the obstacles facing his pursuers.

Brady discovers that the Fishin' Hole demo can hypnotize people without seizure disorders, unlocking the possibility of a mass mind-control operation.

Brady blackmails Dr. Babineau using a modified Zappit, embedding a controlled secondary persona he calls Dr. Z and making Babineau his primary tool.

Hodges recalls seeing Brady holding a Zappit during a clinic visit and recognizes it as the crucial link between Brady and the ongoing suicide conspiracy.

A message from 'Z-Boy' appears on Hodges's old Debbie's Blue Umbrella private chat site, taunting him that Brady is not finished with him yet.

Dr. Babineau blocks Hodges from entering the brain injury clinic, fearing that Hodges may have recognized Library Al as Brady's controlled agent.

Holly discovers Hodges's cancer diagnosis by checking his computer and immediately calls Jerome home from Phoenix.

Barbara tells Holly that a friendly voice inside the Zappit's fish game told her she was worthless and urged her to step into the path of a truck.

Barbara tells Holly that her friend learned about the free Zappit offer through a website called badconcert.com, aimed at survivors of Brady's disrupted concert.

Holly discovers the zeetheend.com website has gone fully live and the group realizes Brady is planning to use social contagion to trigger a mass suicide epidemic.

Barbara identifies a photograph of Dr. Babineau as the well-dressed man who called himself Myron Zakim and gave her a free Zappit at a shopping mall.

Pete tells Hodges his captain has ordered the Zappit case dropped and hands the entire investigation over to Hodges and Holly to pursue on their own.

Hodges threatens Isabelle with press exposure if she refuses to act, forcing the police cyber-crime unit to crash the zeetheend.com website and replace it with a suicide hotline number.

Hodges and Holly leave Jerome behind over his furious protests and drive alone toward Dr. Babineau's remote hunting cabin to confront Brady directly.

Brady forces Hodges to open Fishin' Hole on an infected Zappit and begins working his way into Hodges's mind, intending to make him kill Holly.

Hodges places his father's .38 revolver in the critically injured Brady's hand, and Brady uses his last remaining telekinetic power to pull the trigger.

This pool focuses on the pivotal revelations and choices that define the investigation's turning points, beginning with Brady's breakthrough realization that the Fishin' Hole demo can trap minds without relying on seizure disorders. Each revelation — from the Z-Boy taunt on the Blue Umbrella site to Barbara's identification of Babineau — brings Hodges and Holly closer to an impossible but unavoidable conclusion about Brady's survival. Holly's discovery of Hodges's cancer reframes everything, giving the investigation a sense of urgency and mortality that haunts every subsequent decision. The group's exposure of the suicide website and the severing of Brady's repeater mark the moment he loses his technological advantage and is forced into a direct confrontation. The pool ends at the cabin, where Hodges's final act of placing a gun in Brady's hand — a gesture of mercy that mirrors all Brady has made others do — closes the long arc of the Mercedes Killer.