Sherlock Holmes would refer to a particularly sticky case as a “three-pipe problem”. Hardly anyone smokes now, but there are still some things that can only be managed with a bit of support from a softening vice – not necessarily things that are intellectually taxing, but things that are dull. Things that are relentlessly without merit. Things (and by things I mean novels) that have to be chewed through joylessly, and make easier chewing if you can blunt your brain down to the level of the book.

I cannot say exactly what substance, and in how many units, would make Cari Mora consumable. All I can say is that I did it sober, and I regret it. On the face of it, things should not be half so bad. Thomas Harris is an exemplary thriller writer, and in Hannibal Lecter he created one of the great monsters of fiction. But Cari Mora is not a Lecter novel. In fact, it’s Harris’s first non-Lecter novel since his 1975 debut Black Sunday, and his first novel at all since Hannibal Rising in 2006.

Without Harris's name on the cover it'd be hard to believe this is the work of someone who has so much as read a novel

That’s a 13-year gap, enough to create both a hungry public and – ideally – a well-crafted book to satisfy that hunger. And here is Stephen King among the endorsements, promising that Harris is “as good as ever. Reading his prose is like running a slow hand down cold silk.” Unfortunately, King is so profligate with his endorsements these days that he would probably fill in your parole application if you murdered his grandmother. Without Harris’s extremely recognisable name hanging over proceedings, it would be hard to believe Cari Mora was the work of someone who has so much as read a novel, never mind written a blockbuster series.

The scene is Miami. A house on the beach, once owned by Pablo Escobar, contains something incredibly valuable, and the only person who knows how to access it is a man called Jesús. Too infirm to seek the prize himself, from his hospital bed he sells his precious information to the highest bidder, and doesn’t keep strict terms of exclusivity. With one hand, he pulls the strings of the Ten Bells crime syndicate. With the other, he manipulates a ghastly creep called Hans-Peter Schneider – European born, medically trained and in every regard such a tacky Lecter knockoff that Harris should sue himself for plagiarism.

In the middle, there’s Cari (short for Caridad) Mora herself, seemingly an innocent caretaker looking after the Escobar house, but actually (you can hardly call spoiler on a genre cliche) possessed of a Dark Past that has left her with Surprising Skills. Cari Mora is a good person, who only wants to use her talents to help wounded seabirds: “Caridad Mora, child of war, wanted to be a veterinarian,” one particularly unsilky bit of prose informs us. She is modest and loving, aspiring only to a home of her own and security for her sick aunt. And she is Beautiful, despite the scars on her arms which bespeak the Dark Past that begat her Surprising Skills.

Anthony Hopkins as Hannibal Lecter in The Silence of the Lambs (1991). Photograph: ORION/Sportsphoto Ltd./Allstar

All the women who appear in Cari Mora are either nubile or old, apart from one who is young but also “thick-bodied”. One female character is introduced as “thirty-five and good looking, with some hard miles showing”. You may be relieved that Harris did not bring her into the narrative chest-first, but that’s only because he’s saving himself for a particularly surreal description of some breasts later on, when a character recalls a nightclub where he saw “the girls’ boobs hopping to the clave, one then the other”. If there’s anything more erotic than rhythmically lolloping mammaries, I don’t want to hear about it from Harris.

Still, reading some of the details he offers about the male characters, maybe it’s better just to be a body type. Of a hitman: “He was a thorough man and had eaten two entire avocados for lunch.” (A particular sign of thoroughness?) Of another, wholly tangential, man: “He owned part of a jai alai fronton.” I had to Google “jai alai fronton”, and – spoiler – it did not matter at all. Information dribbles into the narrative with no suggestion of whose perspective it comes from or why we are being told it.

Harris is liveliest when he’s furthest from straight thriller writing. In the descriptions of Miami’s ecology, Cari Mora ascends fleetingly to the level of diverting, and Cari Mora’s backstory, based on real-life case studies of children in combat, delivers some relatively vivid passages. The worst of the novel is the violence. Not because it’s notably unpleasant, but because it’s empty. Without a driving plot or memorable characters to give them weight, the death scenes are just ketchup sprayed on the page. The real three-pipe problem here is what happened to Harris – and his publisher.

• Cari Mora is published by William Heinemann (£20). To order a copy go to guardianbookshop.com or call 0330 333 6846. Free UK p&p over £15, online orders only. Phone orders min p&p of £1.99.