Six oddball but doughty kids fall into the path of a vast and terrible supernatural evil which has come into our world from the outer limits of darkness. They must spend their lifetimes battling it, facing horror after horror in the process.

This is the plot, roughly, of Stephen King’s novel It (his best; no arguments). It is also the plot, roughly, of King’s son Joe Hill’s new horror doorstopper, in which six friends summon the ancient, infinitely malicious dragon King Sorrow from the Long Dark to help them defeat some baddies. Needless to say, their supernatural ritual backfires.

Joseph Hillström King started his career making great efforts to avoid any connection with his famous father, publishing under the pen name he still uses today and avoiding meeting his agent in person (he bears a striking resemblance to his dad). But in this latest novel, he leans into it. There are lines that deliberately echo some of King’s most famous (“The man in black fled across the desert …”); a moment that brings to mind a King plot point (a riddling contest). In this whopper of a novel, Hill is delighting in his family connection, and we delight along with him. King Sorrow is huge, sprawling – and absolutely fantastic.

Back to those friends: five of them are students at the fictional Rackham College in Maine. There’s Arthur, bookish and brilliant, solving Old English riddles in his spare time; Colin, rich, sharp, and prone to trampling anyone who stands in his way; twins Donna and Donovan; the beautiful Allie. And there’s Gwen, who doesn’t study with them, but becomes a key part of their group as they dabble, half believing, half not, in the occult.

Arthur is, for reasons we don’t need to go into here, forced into stealing rare books from his beloved college library by a bunch of local criminals. This tears at his bookish heart, especially when he’s made to take the library’s most valuable and disturbing title: the journal of occultist Enoch Crane (executed “for trafficking with the devyll in 1703”; the book’s jacket is made from his skin). Our Scooby gang read the journal, discover they could summon what Crane describes as a “proud worm, cunning serpent, armoured devil” to help Arthur out with his blackmail problem – and spend the rest of the novel reaping the consequences. King Sorrow will indeed rid them of those troublesome local drug dealers, but they’ll have to choose a new sacrifice each year or become his victim themselves. As Arthur later puts it: “You sow dragon’s teeth, all you get is more dragons.”

Moving through four decades, Hill also moves with effortless ease between genres: as the friends attempt to deal with the situation they find themselves in by, variously, picking people who are obviously evil to sacrifice, or hunting down ways to kill the dragon themselves, we go from thriller to dark fantasy, black-ops torture to romance to horror. My favourite genre switch was to a quest story, deep in the caves below Cornwall, a section sprinkled with JRR Tolkien that was gloriously terrifying.

There are trolls – bridge-dwelling ones and online ones, properly scary and perfectly brought to life. There are magical swords and betrayals, heart-stopping scenes of courage and ones of dreadful evil, both human and otherworldly. It’s a tour de force: a horror novel that is above all a paean to the imagination, and to love and friendship. “We needed a story to believe and now we’ve got one,” says Colin as the friends sit around the table, preparing to summon their dragon into being with the force of their minds.

As Hill puts it in his epigraph: “Hic sunt dracones”. Don’t miss them.