On Memorial Day weekend, 21-year-old Peter Mullen rides his motorcycle to a lavish party at the opulent estate of Barry Neubauer, where Peter works as a car valet. Peter, a Montauk native, receives a perfumed note on rose-colored stationery bearing a license plate number. He finds the corresponding Mercedes, discovers a ribbon-wrapped joint inside, and smokes it. A woman calls on the car phone and invites him to the beach. When he arrives, three men ambush and beat him with professional precision. A camera flashes from nearby bushes. Peter realizes he is going to die and recognizes his killer.
Peter's older brother, Jack Mullen, narrates the rest of the novel. Jack is a 28-year-old Columbia Law student working as a summer associate at the prestigious Manhattan firm Nelson, Goodwin and Mickel. His pro bono assignment is representing Billy "Mudman" Simon, a Texas death row inmate convicted of murder based on pre-DNA-era blood and hair evidence. Jack believes in Mudman's innocence. His colleague on the case is Pauline Grabowski, the firm's top investigator.
That Friday, Jack takes the last train to Montauk, where his father John, his 86-year-old grandfather Macklin "Mack," and his girlfriend Dana Neubauer deliver devastating news: Peter is dead, supposedly drowned while swimming during the party. Jack views Peter's battered body, covered in bruises with broken bones. Mack whispers that the drowning story is "the single biggest piece of crap I've ever heard" (25). Detective Frank Volpi, East Hampton's chief detective, dismisses the death as an accident or suicide. Peter had a new motorcycle and a modeling contract; Jack sees no plausible reason for either explanation.
Meanwhile, Rory Hoffman, the Neubauers' head of security known as "the Fixer," searches the beach and finds boot-shaped footprints and a crushed Kodak film box: evidence someone photographed the scene. Volpi refuses to investigate. A week later, Jack's father collapses and dies of a heart attack in Peter's bedroom. At John's funeral, Mack grips Jack's knee and whispers they will uncover the truth. Jack squeezes back, sealing a pact.
Jack's closest friends rally at the Memory Motel: fisherman Fenton Gidley, Molly Ferrer of East Hampton's Channel 70, EMT volunteer Hank Lauricella, and Sammy Giamalva, a hairdresser who was Peter's best friend. Hank confirms the injuries looked like a stomping and that Volpi never examined the body. They vow to investigate.
Jack's relationship with Dana collapses when he sees her kissing Volpi at her family's estate. He uncovers a bank account holding $187,646 in Peter's name. Sammy reveals that Peter earned money through sexual relationships with wealthy people, including Campion Neubauer, Barry's wife. Dr. Jane Davis, the Suffolk County medical examiner and Jack's former classmate, provides the forensic breakthrough: Peter's lungs show no sign of drowning, and X-rays reveal dozens of broken bones, including a severed vertebra at the top of the spine. Peter was beaten to death and dumped in the water.
The Neubauer interests retaliate. The Fixer forces Fenton off his fishing boat at gunpoint. Hank is fired. Senior partner William Montrose warns Jack that the Neubauers are major firm clients. Pauline agrees to help, uncovering that Neubauer had extortion arrests in his youth whose witnesses vanished and that an escort drowned off his yacht two years earlier, settled for $500,000. They trace the note that lured Peter to the beach to two muscular older men.
Jack confronts Barry Neubauer at the firm; Montrose fires Jack. Intimidation escalates: Surveillance photos of each friend arrive at the Memory Motel with gambling-style odds ranking their vulnerability. The Fixer and an accomplice beat Jack in his garage. Before the inquest, the Fixer breaks into Jane Davis's home, holds her at gunpoint, and threatens to kill her unless she changes her testimony. When the Fixer confronts Sammy demanding photographs from the beach, Sammy slashes his throat with a razor, burns down his house, and disappears, leaving everyone to believe he died in the fire.
The inquest at Montauk Middle School is a rout. Neubauer's legal team, led by Montrose, faces a single young assistant district attorney. A Mayflower Enterprises employee testifies she saw Peter swim into the ocean. A paid expert attributes the injuries to storm surf. Jane, terrorized, recants her findings. Dana testifies she and Peter had been in a relationship, implying he was suicidal. Neubauer produces a phone-bill alibi. The judge rules Peter drowned by accident or suicide.
Afterward, Jane tearfully reveals that Peter was HIV-positive. Jack and Pauline grow closer, and she commits fully to the case. Jack finishes law school and witnesses the Mudman's execution in Texas. Months later, he spots Sammy alive in the East Village but that afternoon watches Sammy fall from a high-rise balcony, thrown by Volpi and an accomplice. In Sammy's mother's basement, Jack discovers photographs documenting Peter's sexual encounters with wealthy people over years, some taken when Peter was as young as 14 or 15. The final photos show Peter with Barry and Dana Neubauer. Jack calls his friends together, and by dawn they have devised a plan.
One year after Peter's death, at the next Memorial Day party, the group abducts seven people connected to the murder and cover-up, including the Neubauers, Montrose, and Volpi. They construct a makeshift courtroom in an isolated, unfinished mansion on the Montauk cliffs, with Mack as judge, Jack as prosecutor, and Molly filming for Channel 70. A signal-scrambling device prevents the FBI from tracing the live broadcast. A handmade sign reads: THE PEOPLE V. BARRY NEUBAUER.
The televised trial generates massive national coverage as networks interrupt programming. Jack dismantles the inquest's false narrative, proving the key witness was rewarded for perjury with a doubled salary. Jane Davis returns to testify truthfully about the threats against her and presents her complete forensic findings: 19 broken bones, skull fractures, and lung tissue inconsistent with drowning. Stella Fitzharding, a close friend of the Neubauers who appears in the photographs, admits Peter blackmailed them and demanded millions when Neubauer's corporate merger was announced, providing a motive for murder. Campion testifies voluntarily, revealing she orchestrated the photography as insurance against her husband and admitting she set up the circumstances leading to Peter's death.
Jack displays the explicit photographs and dark images from the murder night, which capture glimpses of Neubauer's watch and Volpi's face. Neubauer offers $10 million to stop the proceedings; Jack refuses. He reveals that Neubauer is HIV-positive and has concealed his status, presenting affidavits from seven people who believe Neubauer knowingly infected them. Jack calculates a potential sentence of 144 years. Neubauer breaks down. Jack declares: "You killed him. I can't prove it, but I got you anyway" (339).
The hostages are released, and Jack, Mack, and Pauline surrender peacefully. During a recess, Volpi had briefly escaped; recaptured, he admitted Neubauer had his men kill Peter. Five months later, Neubauer is on trial for manslaughter with 12 additional cases pending. Montrose is under FBI investigation. Volpi has been arrested for Sammy's murder. Campion has been indicted as an accessory. Jack, Mack, and Pauline plead guilty to kidnapping and face a minimum of 20 years. Invoking a federal guideline that permits reduced sentences when cooperation leads to prosecution, the judge sentences all three to time served and 600 hours of community service with the Legal Aid Society's Capital Defenders Unit. The courtroom erupts in applause. Jack remembers Peter as a small child climbing into bed with him and saying, "I like hearing your heart beat, Jack" (354).