Anna, five, and her brother Stick, three, are camping with their parents in remote Canadian wilderness. Anna hears her mother yelling. Suddenly their father opens the tent, carries them out and shoves them inside the family's giant Coleman cool box. He locks it, wedging a rock under the lid to allow them to see a little.

They don't know what is going on, but it gradually becomes clear to the reader that a bear is attacking their parents. From this tense opening, the novel follows the fortunes of the two children as they are forced to fend for themselves.

The Bear, Claire Cameron's second novel, is narrated throughout by Anna. It's a bold authorial move: it takes time to get used to her voice, a stream of young, innocent consciousness, which, because she doesn't really understand what she is seeing, initially seems to obscure the action, as if one were viewing it underwater.Yet it's this gap between Anna's opaque comprehension and the reader's deduced greater knowledge that gives the simple prose its power.

From inside the Coleman, Anna (who thinks the bear is her neighbour's dog Snoopy) hears a noise. "Snoopy is eating the bone and I can hear the snap snap snap of his jaws on the bone." Later, the "black dog" as she calls it, starts biting the Coleman. "The black dog has tomato juice on its paw and some of it paints on to Coleman's white lip. The tongue comes out and licks the juice..."

While the reader can work out that the bone is that of one of her parents and the "tomato juice" is their blood, Anna, who is supplying the information can't (or perhaps won't let herself). Shocking.

The story then becomes an interesting portrayal of how young minds cope with abandonment, the loss of authority and guidance, survival and grief. Whether you believe in Cameron's version of a five-year-old mind or not – there's the occasional anachronism in Anna's thoughts and actions – she manages on the whole to capture a childish view of the world with authenticity and charm. While struggling to get Stick's T-shirt off, Anna admonishes him: "Stop growing your head."

It's a distinctive narrative voice, no doubt, but one that might grate with some. If it doesn't, the reward is striking images that stick in the mind, a blend of Anna's interpretations of events and the reader's imagination. On finishing the book, this reviewer, now fully attuned to her perspective, went back to the beginning and reread the bear attack scene. It was even more haunting the second time around.

Harvill Secker £9.99. Order for £8.99 (free p&p) from the Independent Bookshop: 08430 600 030