Port Mungo by Patrick McGrath

Hot and bothered

It is a rare thing to finish a novel feeling both dazzled and slightly nauseous, but when it happens, the odds are that you have been reading Patrick McGrath. Like the toxic lullabies of his most abiding literary forerunner, Edgar Allan Poe, McGrath's fiction is deeply unsettling to the soul. The power of Gothic fiction is to seduce and disturb in equal measure, and in McGrath's new novel, the smooth and revoltingly compelling Port Mungo, the creepiest aspects of its tradition hold sway.

The narrative begins in New York with the recollection of the painful aftermath of a teenager's death. The dead girl is Peg, daughter of the artist Jack Rathbone and his dissolute companion, Vera. The events that lead to Peg's drowning, and expand beyond it, are recounted by Gin Rathbone, Jack's grimly loyal sister, who makes no attempt to endear herself to the reader: "I suppose I am rather - oh, detached - distant, aloof, snobbish, even, and have been called all these things, also cold, stiff, and untouchable."

Yet it is these very characteristics - or rather Gin's fastidiousness in owning up to them - that establish her as a narrator you can trust. She doesn't try to hide her intense, on-the-edge-of-unhealthy love for a brother she has always idolised, defended and, when necessary, colluded with.

But nothing, in the end, is as it seems. Swinging to and fro across the years, Gin recounts how Jack, as a young art student in London, falls under the spell of the older, more established Vera. Vera is a very particular brand of bad news: talented, feckless and self-destructive, she exerts a sexual and psychic influence over Jack, which Gin, the bereft, unwilling gooseberry to their folie à deux, is unable to counteract. After a whirlwind affair, Jack and Vera move to New York; from then, Gin is forced to chart the couple's movements from a distance, making occasional forays into their increasingly alcohol-fuelled existence. Nagged by what seems artistic restlessness, Jack and Vera move to Miami and then Havana before finally setting up home in an old banana warehouse in the unlovely town of Port Mungo, a festering Honduran backwater.

Here, in a place where "time was the problem, debauchery the common solution", the years pass: two daughters are born and Jack paints against a sweaty backdrop of mangrove swamps, while Vera, whose talent curdles to nothing, drinks and has affairs. When, aged 16, Peg is found drowned in a mangrove swamp in obscure circumstances, her sudden, agonising absence leaves Jack - and the paintings he goes on to create - haunted by a residue of inexpressible guilt. Peg's younger sister Anna is sent to England, leaving Vera to disappear again and Gin to reclaim Jack in New York. But 15 years later, Anna reappears, and the wound of Peg's death is reopened.

It is at this point that the narrative, which until now has run on a steady, slow burn and encompassed three decades, begins to combust completely, with a shift in momentum that almost induces vertigo. There are times, in the final third, when it is almost too painful to carry on reading this story of familial dysfunction, where morality is sacrificed on the altar of art. It is the sanity of the devoted but austere Gin that keeps you turning the pages, and because of Gin the ugly secret at the heart of the novel affects you so painfully. You have shared Gin's prejudices, disappointments and concern for 200 pages, so when you realise - at the same moment she does - that love can blind itself to truth, it is too late.

Perhaps novels this disturbing should carry a health warning. When I had finished reading Port Mungo, I felt queasy, haunted, polluted, disoriented and defiled by a work of utter brilliance.

Liz Jensen's new novel, due in July, is 'The Ninth Life of Louis Drax'