By Niccolo Ammaniti

Translated from the Italian by Jonathan Hunt

Canongate. 200 pp. $23

If one had to pick fiction's single overarching theme, it would probably be the transition from innocence to experience. Under this umbrella huddle innumerable love stories happy and tragic, scores of Bildungsromane, every mystery ever written and a handful of splendid modern novels about the end of childhood: A High Wind in Jamaica, Lord of the Flies, To Kill a Mockingbird, The Cement Garden and now Niccolo Ammaniti's I'm Not Scared.

Born in 1966, Ammaniti has already brought out three novels and a collection of stories, won Italy's Viaggio-Repaci prize and been acclaimed by Il Giornale "the best novelist of his generation." His style -- at least in I'm Not Scared, which has been a bestseller and translated into 20 languages -- harks back to the sharp, evocative prose of Giuseppe di Lampedusa or Leonardo Sciascia rather than the mannered erudition of Umberto Eco or late Italo Calvino. There's nothing in the least postmodernist or tricksy about Ammaniti's clean, spare writing. This economy carries over into his book's setting and characters -- a small Southern Italian village made up of four families and some surrounding wheatfields. The action, too, takes place over a mere week or so during the hot summer of 1978. Within this apparently bland regionalist frame, Ammaniti encloses a suspense story as gripping as any Hitchcock classic. In fact, I'm Not Scared might just as well have been named after Joseph Hayes's old thriller The Desperate Hours.

Naturally, it starts off as a kind of idyll. The children of the village of Acqua Traverse -- a pack led by the mean, sadistic "Skull" -- are racing up a hill. When 9-year-old Michele hears his 5-year-old sister Maria stumble and fall, he stops to help her. This is our first glimpse of Michele's instinctive kindness and humanity: By coming to Maria's rescue, he cannot win the race. Shortly afterward, Skull attempts to compel pudgy Barbara to show her privates as the forfeit for coming in last. To spare a girl he doesn't even like, Michele takes over the penalty, which is altered to a dangerous climb through an abandoned farmhouse. When Michele slips and falls, he lands on an old mattress that lies on top of some corrugated metal. He pushes aside the mattress, then the sheet of steel, and peers down into a hole. Inside the hole lies a boy.

"He was naked. About the same height as me, but thinner. He was skin and bone. His ribs stuck out. . . . I touched his hand with my toe, but it remained lifeless. I lifted the blanket that covered his legs. Round the right leg he had a big chain fastened with a padlock. The skin was scraped and raw. A thick transparent liquid oozed from the flesh and ran onto the rusty links of the chain, which was fixed to a buried ring."

Michele doesn't tell the gang about what he has discovered, and for a while hopes that he is suffering from delusions. Instead, brother and sister return to the village and learn, to their intense joy, that their truck-driver father is back home after several weeks away. He has brought a new pair of glasses for Maria and a model of a gondola to set on top of the little television set. Despite an evening of family happiness, Michele suffers from nightmares: What if the boy isn't dead? He might be "scratching at the walls of the hole with his fingers and calling for help." But why was he in the hole in the first place? Maybe he'd been caught by an ogre or possibly he was a werewolf kept chained up in the dark so that the moon wouldn't transform hin into a ravenous beast. Or could he even be his own insane twin brother, or . . . ?

The next day, when Michele tries to tell his father about the boy, the truck driver needs to hurry off on some errand. So the brave 9-year-old pedals his old bike back to the pit, where he makes further discoveries. Still hoping to unburden his soul, Michele is yet again thwarted because his father flies into a rage over his son's all-day absence and sends him immediately to bed without another word. Meanwhile, the children of the village continue to kick soccer balls and play hide-and-seek, romp with a stray dog, climb trees.

So life goes on -- sort of -- in impoverished Acqua Traverse. Yet the boy is still in the hole. A mysterious old man -- a friend of the father's -- comes to stay at Michele's house. Skull's thuggish ne'er-do-well older brother reappears and starts whizzing around town in his car and glowering at the little kids. Michele again visits the abandoned farmhouse, partly to explore a room that looks to be in occasional use. To his consternation, he notices a cooking pot with apples painted around the outside. It's a design he has seen before.

From this point on -- and be assured that I have left out many plot details -- Ammaniti's novel begins to accelerate, grow darker, ever more ominous. Almost certainly the adult reader will tumble to the secret long before Michele does. But that doesn't really matter. The last 20 pages are still a heart-stopping race against time, worthy of Cornell Woolrich, and the finale a neatly prepared shocker.

Though the deepening sense of menace is inescapable, I'm Not Scared offers other pleasures beyond those of a compact thriller: a movingly understated portrayal of a mother's fierce love for her son; spot-on evocations of childhood (little Maria's habit of hiding meat she doesn't like beneath the struts of the kitchen table); insight into a poor family's simple dream of visiting the seashore and eating mussels; Michele's puppyish adoration of an 18-year-old cook:

"I was very keen on Antonia, she was beautiful and I would have liked to go out with her, but she was too old and she had a boyfriend in Lucignano who put up television aerials."

But I'd better end this review before revealing any more of the narrative excitements and twists of I'm Not Scared. If I'm not careful I might even let out some of what happens after the dead boy begins to speak. *

Michael Dirda's e-mail address is dirdam@washpost.com. His online discussion of books takes place each Thursday at 2 p.m. on washingtonpost.com.