My daunting brief: to tell you about Hanya Yanagihara and her new, uncategorisable 720-page novel in 550 words. It’s the book-reviewing equivalent of a heated round of Articulate. Bums on the edge of the sofa, team. Flip that egg-timer. Here goes!

American, born 1974, childhood spent largely in Hawaii. Debuted with The People in the Trees, 2013: clever, concept-led story about a fictional island whose inhabitants stumble upon the secret of extreme longevity. Best known for her second novel, the 800-page A Little Life, sold more than a million copies, shortlisted for the Booker. Come on, you know this one! Four gay friends, but mainly about Jude, the victim of terrible child abuse, addicted to self-harm. If you didn’t read it yourself you’ll know someone who did, and either loved it for its unrelenting darkness or dismissed it as gratuitous melodrama.

The new book, To Paradise, has three sections: 1894, 1994, 2094. Location: New York, specifically a townhouse in Washington Square. The novel’s 1894 is an alternative, semi-utopian version of the past. Gay marriage is permitted. Fragile David Bingham, the scion of a banking family, is being encouraged to marry the wealthy Charles Griffith. Really he loves Edward Bishop, an impoverished music teacher who might be practising a con trick on him.

1994: our recent past. The Aids pandemic. A man called Charles Griffith lives in the big townhouse with his younger lover, David Bingham, the descendant of Hawaiian royalty. They host a farewell party for an HIV-positive friend who is actually dying of cancer and plans to travel to Switzerland to end his life. There is also a long, rambling letter from David’s father (another David) explaining how he tried to establish a utopia of two in the Hawaiian wilderness, manipulated by his controlling best friend, Edward.

2094: full-bore dystopia. Charlie Griffith, a young woman badly damaged by childhood illness, lives with her husband Edward on one floor of the original Washington Square house, now divided into apartments. The world has suffered successive pandemics. ‘Fear of disease, the human instinct to stay healthy, has eclipsed almost every other desire and value they once treasured.’ There is heavy surveillance. There are extreme climate events. There are ‘centres’ for the infected that sound more like death camps. One day, Charlie befriends a mysterious man called — you guessed it — David. But can she trust him?

The historical fiction is pacy and cogent, despite some hokey dialogue. The farewell party in 1994 is very strong: a depiction of ordinary sadness more affecting than anything in A Little Life. The letter from Hawaii feels shoe-horned in, like something Yanagihara’s had lying around for a while. The final, overlong section is pure panic porn, and my god is it gripping.

Ingeniously, improbably, all this hangs together to make a sui generis whole that’s decidedly greater than the sum of its very weird parts. The thing with the repeating names: it sounds bonkers, but it works. The genes of the same basic story express themselves again and again in myriad variants. Utopias, dystopias, nested narratives, multiple genres, intricate world-building. Shameless swathes of exposition, crude indulgence of our darkest fears. Formidably fluent, morally simplistic, conceptually audacious, aesthetically overblown.

Still haven’t figured out what it is I’m describing? Frankly, neither have I.