I have been one acquainted with the night.

Christopher Snow is athletic, handsome enough, intelligent, romantic, funny. But his whole life has been affected by xeroderma pigmentosum, a rare genetic disorder that means his skin and eyes cannot be exposed to sunlight. Like all Xpers, Chris lives at night - and has never ventured beyond his hometown of Moonlight Bay, a place of picturesque beauty and haunting strangeness; he knows it as no one else can possibly know it, is intimate with its shadows and darkest hours. Despite the limitations imposed by nature, he has always been determined to lead the fullest life and, with the help of family and friends, he has on the whole succeeded.

But for Chris - and all the inhabitants of Moonlight Bay - a terrible change is about to happen; a change of potentially catastrophic proportions.