In Stephen King’s 1987 novel Misery, Annie Wilkes isn’t happy with the ending of Paul Sheldon’s latest book, so she forces him to write another one, chopping off various body parts to keep him on track along the way. Almost 30 years later, Morris Bellamy, the pasty-skinned, red-lipped villain of King’s new novel Finders Keepers, takes a less nuanced approach when confronting his own literary hero. Only pages in, John Rothstein, the novelist dubbed “America’s reclusive genius” by Time magazine, has been shot in the head.

Morris has come to Rothstein’s remote New Hampshire house with a pair of thugs, ostensibly to rob the elderly author. But, really, he’s heard rumours of the dozens of notebooks Rothstein has filled with his writing in the decades since he retired from public life entirely, and is desperate to find a new ending for Rothstein’s creation, Jimmy Gold. Jimmy is “an American icon of despair in a land of plenty”, according to Time; he’s the star of Rothstein’s era-defining “Runner” trilogy, and coiner of the slogan that adorns the T-shirts of students across the US: “Shit don’t mean shit.”

“You created one of the greatest characters in American literature, then shit on him... A man who could do that doesn’t deserve to live,” says Morris, before fleeing the scene, notebooks and cash and (somewhat briefly, sadly for them) accomplices in tow. Hyperventilating with anticipation at the prospect of reading Jimmy’s story, but aware of the forces of law on his trail, he buries his treasure in an old chest, only to end up with a life sentence for another crime.

More than 30 years later, the chest is discovered by Pete Saubers, a boy whose family is in dire financial straits after his father fell victim to the villain of King’s previous thriller, Mr Mercedes. Pete finds a clever use for the money, and revels, in solitary bliss, in Rothstein’s “nasty, funny, and sometimes wildly moving prose”.

King flits between the two stories, Pete and Morris’s, past and present, slowly building up to what has always been coming: Morris’s release, still “batshit-crazy” on the subjects of Jimmy Gold and John Rothstein, and his reclaiming of what he believes is his.

Finders Keepers is the sequel to Mr Mercedes, a straight thriller that won King the top US crime award the Edgar, and the second volume in a projected trilogy about retired detective Bill Hodges (to be completed with The Suicide Prince). Hodges, now running the investigative firm Finders Keepers, is reunited with his fellow investigators, Jerome and Holly, in this new case. But he’s also still obsessively visiting Brady Hartsfield, Mr Mercedes’ killer, who has awoken from a coma, but is, apparently, still catatonic.

At fewer than 400 pages, Finders Keepers isn’t a long book by King’s doorstopper standards, but it’s expertly plotted, a series of pieces falling into place with almost audible satisfaction as the author burns towards his suitably horrific climax. Just as Pete and Morris are with Rothstein, once you’re hooked, you’re hooked; I completed the novel in the small hours despite an exhausting day of planes and trains – I just couldn’t leave be.

Horror and thrills aside, Finders Keepers is just as fascinating for its fresh take on a topic that perennially fascinates King: the relationship between a writer and their fans. Rothstein is a sort of melange of the great American novelists; the reclusive Salinger, with the New Hampshire hideaway and the story (“He wrote that book about the kid who got fed up with his parents and ran away to New York city, right?”); Pynchon with the unclaimed National Book award; Roth in the name; Updike’s Rabbit quartet. At the rate King publishes, it must have been written after the death of JD Salinger, and after the rumours of the cache of novels he kept that were never published. “Nobody with his kind of talent has a right to hide it from the world,” says Morris of Rothstein. I can’t be the only one who’d love to hear King’s take on Salinger.

Finders Keepers is published by Hodder & Stoughton (£20). Click here to buy it for £16