Cate Newhouse, a twenty-two-year-old unpublished writer living in a cramped shared flat, receives an invitation to attend one of Arthur Fletch's legendary salons on his private Scottish island, Skelbrae. Fletch is the world's most famous author, known for his bestselling Petrarch crime series. The invitation comes through Cate's agent, Eleanor Vandenberg, who also represents Fletch. Despite self-doubt and dire finances, Cate accepts.
Six writers converge on the island. Sienna and Malcolm Buchanan co-write thrillers under the pen name Penn Stonely, though Sienna does nearly all the creative work. She plans to leave both the partnership and the marriage but agreed to attend one last time in exchange for an amicable divorce. Also present are Millie Mitchell, a young adult author; Jaxon Knight, a sci-fi writer whose publisher recently canceled his series; Kenzo Gray, a Japanese American horror writer; and Priscilla Renée Fox, a Black romance writer. From the boat, Malcolm spots a figure on the cliff wearing Fletch's signature red hat, but the figure retreats without acknowledging them.
The writers sign nondisclosure agreements in the castle's drawing room. When Fletch fails to appear, Eleanor and a man introduced as Rufus Beaumont, Fletch's editor, announce that Fletch drowned a month ago. His death has been kept from the press, and his final Petrarch novel remains unfinished, stopping roughly 10,000 words short. One writer will ghostwrite the ending and receive the remainder of Fletch's advance plus a three-book deal with Merriweather Press, totaling 2 million dollars. Eleanor notes all six are midlist authors who sell modestly but have never broken through to bestseller status. The writers surrender all devices to a time-locked safe set for 72 hours and receive typewriters with color-coded paper for blind judging.
Sienna reads the entire manuscript while Malcolm sleeps; the story cuts off mid-sentence as detective Julia Petrarch closes in on the killer she has hunted across four books. Over dinner, the writers trade bitter stories about the publishing industry. Kenzo suggests Fletch might not be dead, sparking debate about the cliff figure and a rumored book Fletch commissioned, cast in solid gold.
After midnight, Millie screams. Someone has typed "GET OUT" on a sheet of her pale-blue paper while she slept behind a locked door. Malcolm notices the letter G is misaligned, meaning the note came from a different typewriter. Samples from all six machines match perfectly, leaving the source unidentified. Kenzo shows Sienna a miniature replica of the castle in the library, revealing hidden passageways between bedrooms and a secret staircase to Fletch's locked attic room.
Sienna picks the lock and climbs to that room, where she finds evidence Fletch was struggling with the ending. She types "GET OUT" on his typewriter, confirming the misaligned G matches; someone else broke in before her. A trapdoor leads into Millie's room, explaining how the intruder delivered the note. Sienna folds the test note and pockets it. As the hours tick down, her partnership with Malcolm collapses. She declares Penn Stonely dead and, after Rufus grants her permission to compete independently, experiences a sudden flash of inspiration for Fletch's ending.
A flashback reveals a crucial deception. "Priscilla" is actually Ava Paulson, Fletch's real senior editor, who went undercover to evaluate the candidates' personalities. "Rufus" is Holden Merriweather, Ava's assistant, whose uncle owns the publishing house. After Ava berates him for breaking protocol, Holden encounters the island's elderly groundskeeper, Angus, wearing Fletch's red hat in the dark. Angus is the figure Malcolm saw from the boat. Terrified, Holden mistakes him for a ghost, flees to Fletch's yacht, and escapes, stranding everyone.
That night, Sienna brews tea from the kitchen, unaware someone has laced it with sleeping pills. Drowsy and disoriented, she hauls her typewriter toward the stairs. At the top, a pair of hands shoves her from behind. She tumbles down and dies on the landing beneath a stained-glass portrait of Julia Petrarch.
The group discovers they are stranded: no boat, their phones locked in the safe, and no way to open it. Malcolm spirals into grief after finding a "GET OUT" note in Sienna's pocket, not knowing she typed and pocketed it herself. He interrogates each writer but identifies no killer. Kenzo, a forensic technician in his day job, examines the scene and concludes the fall appears accidental.
Malcolm finds Sienna's notebook containing her ending but cannot decipher her shorthand. Near the cliff, the wind scatters pages he tears out in frustration. He lunges after one, and the cliff crumbles beneath him. Jaxon, finishing a run, sprints to help but cannot reach him. Millie, watching from a distance, accuses Jaxon of pushing Malcolm. The group locks Jaxon in his room. Kenzo, holding an antique ax taken from the castle walls, turns the key.
Locked in, Jaxon breaks through months of writer's block and begins typing, but an intruder enters through the hidden passage and strangles him with his own resistance band. His pages are stolen. When the body is found, the group discovers the passage connecting Jaxon's room to Millie's, casting suspicion on her. Millie storms into Priscilla's room and finds Jaxon's stolen pages on the dresser and her own submitted pages under the pillows. She grabs a decorative mace and holds Priscilla at bay. As Millie advances, Cate strikes her from behind with a massive golden object, killing her.
The weapon is the legendary golden book, which Cate found hidden beneath the foyer floor using a clue from the miniature castle in the library. Ava drops her disguise, but Cate confesses to everything: the threatening note typed on Fletch's typewriter, the drugged tea, shoving Sienna down the stairs, strangling Jaxon through the hidden passage, and planting pages to frame Priscilla. Malcolm's cliff fall was genuinely accidental, though Cate watched from the attic and let Jaxon take the blame.
Cate reveals her true motivation: Her mother wasted her life chasing publication, accumulating debt and neglecting her daughter. Cate never wrote her own manuscript; she fed Fletch's backlist into an artificial intelligence (AI) program and generated a novel mimicking his voice, which Eleanor signed without detecting the fraud. She wants only the golden book's monetary value and escape from poverty. Ava bluffs that she can open the safe, buying time. In the foyer, they discover Kenzo's body impaled on the antler sculpture; Cate shoved him when he returned for the ax. When lightning distracts Cate, Ava flees into the storm. After a chase across the island, a struggle in a small rowboat ends when Ava strikes Cate overboard with an oar. Weighed down by the satchel containing the golden book, Cate sinks beneath the waves.
Days later, Eleanor arrives to manage the fallout. She persuades Ava to ghostwrite the ending for a million-dollar advance, but when Ava retypes Fletch's final line, her mind goes blank. A coda reveals she eventually leaves publishing. Merriweather Press releases the novel unfinished, an idea from Holden, who is promoted to senior editor, and the book spends 24 weeks on the bestseller list as fans debate the ending for themselves.
The epilogue follows Kenzo, who survives. After Cate's attack, he drags himself free and is found by Angus, who stitches his wounds and radios for help. Kenzo signs with Eleanor and publishes a bestselling horror novel disguising the Skelbrae ordeal as fiction. At a packed book signing, he is the sole survivor of the island's deadly competition, transformed from a midlist horror writer into a literary star whose story is built on the broken dreams of his fellow writers. The line of fans stretches so long he cannot see its end.