Peter Pan in Scarlet by Geraldine McCaughrean

I wouldn't count myself among the host of "Wendy worshippers and Hook aficionados" Geraldine McCaughrean felt at her shoulder when she sat down to start work on a sequel to Peter Pan. Only a veteran of more than 130 children's books could hope to see them off. But a return voyage to Neverland, your passage arranged by way of a competition run by Great Ormond Street Hospital, must rank as one of the most nerve-racking journeys undertaken by a modern author.

It's not as though the Pan story was lacking in imitators: prequels, sequels, revolting Disney movies, not to mention the slew of works picking over the life of its creator, J M Barrie. At the end of the original novel, Wendy and the Lost Boys have been claimed by adulthood; Hook by death at the jaws of a crocodile. To these problems, and all others, McCaughrean has endlessly imaginative solutions.

Ravello, a circus ringmaster, has come to Neverland, with an array of frightening beasties. Known as the "Ravelling Man", this woolly, indistinct figure - not so much a person as a "very tall cardigan" - finds a way to insinuate himself into Pan's retinue as valet. But what of those Lost Boys, all grown up now: judges, baronets and fathers? Well, they reappear, summoned to Neverland by unsettlingly vivid dreams, after donning their own children's clothes and shrinking down to their former sizes. Wendy, too, reprises her role as Mother and even Tinker Bell is wished back into existence.

So, with the original cast on board, what can McCaughrean find to do with them? The answer is a cunning combination of the best of Barrie's, and her own, previous work (with just a dash of inspiration from the film versions). In last year's The White Darkness, McCaughrean took a well-known story of adventure and exploration and reinvented it, as her young heroine set off across Antarctica with the spirit of the dead Captain Oates for company. Here, the reformed "League of Pan" set out on a classic quest for buried treasure but find something so sinister hidden at the summit of Neverpeak that it overturns not only their ideas about lost treasure but about Pan himself.

McCaughrean's book, like Barrie's, is as refreshingly dark and unsentimental as a book about fairies and lost babies can be, and it's hard to see how she could have done it better. There are some cast members who don't return for the sequel: Michael Darling, along with many of the pirate crew, has entered the ranks of eternally Lost Boys by joining up for the Great War. Neverland itself has changed from summer to autumn, polluted by Hook's poison. However, McCaughrean does allow herself, and us, an ending filled with the kind of happy reunions which Barrie clearly felt - perhaps for reasons obvious from his own biography - unable to provide.

And what about Peter Pan himself? Still as sulky, petulant and, frankly, unappealing as ever. But why is he dressed in scarlet? And wearing an Eton boy's white tie? Telling would be simply, as Hook would put it, terribly bad form.