(Random House)

Enter if you dare!

That’s more warning than victims get in David Mitchell’s devilishly fun new novel, which clawed its way to life from the ectoplasm of Twitter. Just in time for Halloween, “Slade House” opens its rusty door on a ghost story that dresses up all the dusty old tropes with Mitchell’s spirit and wit. His fans will need no enticement, but for the curious, too intimidated by “Cloud Atlas” or even last year’s “The Bone Clocks,” this little book will go down like fresh gummy worms.

If you’ve found Platform 9¾ at King’s Cross station, you’ll have no problem locating Slade House. It’s just a step to the left. Go down the narrowest, darkest alley you’ve ever seen. The owners of Slade House are expecting you. You’ll find a black iron door — munchkin-size — with no knob. Push gently. Inside the walled yard lies a sprawling garden and a hulking mansion on a piece of property that can’t possibly exist between the ordinary houses on both sides. But by the time you’ve gone this far, you’ve already left three dimensions behind, so don’t worry about the real estate.

Worry, instead, about your hosts.

Norah and Jonah — twins — look surprisingly youthful for being almost 120. It must be the garden air. Or something.

Their home is a kind of lethal Brigadoon that materializes for a spell every nine years. Norah and Jonah take on different external characters each time as they welcome some tasty new guest. “Slade House” presents us with five chapters: five distinct and deadly reappearances from 1979 right up to this year. Each one begins with a slightly confused approach to the house, a seductive welcoming, a fit of confusion and then the horror, the horror.

That structure sounds repetitive, like five identical tombstones lying in a row. As Scrooge begged Marley’s ghost, you may ask, “Couldn’t I take ’em all at once, and have it over?” But the sticky web of repetitions and parallels in these stories grows increasingly ominous and, yes, ghoulishly funny. And Mitchell includes plenty of nice bits of parody, including references to “The X-Files” and “The Da Vinci Code.”

Each hapless guest who arrives at Slade House succumbs to the hosts’ sorcery, their “Theatre of the Mind.” Before realizing what he’s really in for, one of them jokes, “Tonight feels like a board game co-designed by M.C. Escher on a bender and Stephen King in a fever.” The novel isn’t nearly so headache-inducing as that suggests, but Mitchell is something of a magician, with fluid moments of mental manipulation. When Norah and Jonah bend their plastic world, their victims begin to see things through “kaleidoscopic drug-tinted spectacles.”

The story opens with Nathan, a 13-year-old Dungeons & Dragons player dragged to Slade House by his grasping mother. He’s a Valium-filching nerd who endures his classmates’ taunts with stoic introspection. As Mitchell showed in “The Bone Clocks” and his autobiographical novel “Black Swan Green,” he’s one of the most charming and poignant recorders of adolescence. Nathan enjoys hanging out in the garden with Jonah long enough to imagine that “maybe this is like having a friend.” (Not really, dear boy.) At the climax, as the Potemkin estate begins to dematerialize, he thinks, “My shriek’s like a shriek shrieked into a traffic cone all stifled and muted.”

Such cries may pull on your heartstrings, but Jonah licks his lips (Do fiends have lips?) and notes that “a sprinkle of last-minute despair gives a soul an agreeably earthy aftertaste.”

Despite the heavy mantle of doom, it’s not as though these poor guests don’t have any chance of escape. In fact, each of them gets tantalizing clues of impending danger. Maybe it’s a whispered warning from a disembodied voice (“Run now, as fast as you can”) or something odd about the decor (How could the hosts have a painting of you in the hallway dressed as you are right now?). But Norah and Jonah — whatever they may be — have been maintaining this deceptive “lacuna” out of time for decades, so they definitely have the upper paw.

Fans of Mitchell’s previous novels will enjoy the usual sprinkling of allusions and echoes, particularly a familiar character who wants to put a stop to these two “soul vampires,” but it won’t be easy. It may not even be possible.

The genesis of Norah and Jonah’s lair is weird but not much weirder than the genesis of “Slade House” itself. Last summer, Mitchell published the first chapter as a series of hundreds of tweets. Ordinarily, I would rather have my soul sucked from a hole in my skull than read a novel that started on Twitter, but this breezy string of murders is a fiendish delight.

And in an even stranger blend of real-time and book-time, Mitchell is currently tweeting as a character from the final chapter of “Slade House.” You don’t have to take part in these extratextual shenanigans to enjoy the novel, but as the moon rises for Halloween, you might want to wander down that narrow alley.

Go ahead. Enter.

Ron Charles is the editor of Book World. You can follow him on Twitter @RonCharles.

Slade House

By David Mitchell

Random House. 238 pp. $26