FICTION: Mother's Day in a small town in Mississippi, and everyone in the Cleve household is rushing around organising a big family get-together, worrying about the menu, the flowers and the good linen napkins.
But when nine-year-old Robin is found hanging in a black-tupelo tree in the back garden, that's the end of life as the Cleves have always known it. Was the child murdered? Who would do such a thing? Why? Twelve years later, not only has the mystery not been solved, but the tragedy is never discussed. Its repercussions, of course, have spread like a stain across the family. Robin's mother has retreated into a dreamy world of pills and indifference; his father has left to set up house with a mistress at a discreet distance; a battalion of elderly great-aunts battle on, putting a variety of brave faces on the devastation. None of which is enough for Harriet. She was just a baby when her brother died, but now, at 12, raised on a high-energy literary diet of Stevenson, Conan Doyle and the diaries of Scott of the Antarctic, she is full of righteous indignation and determined to find and punish Robin's killer.
The Little Friend begins as a thriller would, with a death, and a puzzle to be solved, and a central character set on solving it. While Donna Tartt is clearly interested in the thriller genre and its conventions, however, The Little Friend is also part family saga, tracing the Cleves' slide from southern gentility into suburban ordinariness in a single generation; the Cleve great-aunts, with their home baking, flowery frocks and scented handkerchiefs, are a delight . But what family saga would feature the Ratcliff brothers, edgy and delusional on amphetamines they cook themselves under cover of a taxidermy business, and their lunatic hillbilly granny? Though the Cleves and the Ratcliffs are practically neighbours, they inhabit parallel universes - until Harriet decides that Danny Ratcliff murdered her brother.
It would be a crime in itself to give away the plot of a 500-page novel. Let's just say that, Harriet being a big fan of Rudyard Kipling, it involves snakes. "Be still, o little one, for I am Death. Another cobra had said that, in something else by Kipling. The cobras in his stories were heartless but they spoke beautifully, like wicked kings in the Old Testament . . . " And while we're digging out quotations, we might as well note Tartt's way with acerbic one-liners. A car full of older girls, all hairdos and hormones, shoots past Harriet "in a jingly rocket-trail of pop music". A preacher offers "the frozen smile of the fanatical blessed, radiating either hope or idiocy, depending on how you looked at it".
All page-turning stuff and immensely entertaining; but easily the best thing about The Little Friend is its sense of place. Donna Tartt's Mississippi is so real it oozes out the edges of the book, a potent blend of dust and slime and sweat and crumbling decay. Swamps whine with mosquitoes; water is always brackish and stale. As a metaphor for the emotional quagmire in which her characters are trapped, it's not subtle, but it is shiver-inducingly memorable. If The Little Friend was a thriller it would have to be filed alongside others which are similarly rooted in particular landscapes - James Lee Burke's Louisiana and Carl Hiaasen's Florida spring to mind, and that's pretty good company.
In fact, though, this is a novel about innocence and the loss of it. Fierce, independent and stubborn, Harriet dominates the action like a whirlwind. When she wants to find out how to load a revolver, she consults the Encyclopaedia Britannica. If there's nothing for dinner she eats lollipops, or crackers. Her friend Hely lives in a normal house, "modern and bright: corn chips and Ping-Pong, stereos and sodas, his mother", as Harriet muses bitterly, "in T-shirt and cut off jeans running around barefoot on the wall-to-wall carpet". For all her courage and resourcefulness, however, Harriet is just a kid, and her view of the world is fatally skewed, so don't expect a neat, tidy ending.
A couple of minor quibbles: first, the cover is awful; ugly, creepy and pointless. Second, hardbacks this size are just too heavy for light reading. But if you want a book to climb into and pull over your head, page by macabre, hilarious page, The Little Friend will serve you very well indeed.
Arminta Wallace is an Irish Times journalist
The Little Friend. By Donna Tartt. Bloomsbury, 555pp. £16.99