The Stones are Hatching by Geraldine McCaughrean
Phelim was the only one, they said, the only one who could save the world from the Hatchlings of the Stoor Worm. The Stoor Worm, who had been asleep for aeons, since it was vanquished by the hero, Assipattle, was beginning to waken. It was the booming of the guns, the cries of the wounded, the dreadful sounds of war that had woken it, and now its Hatchlings were abroad to terrorize the people who had forgotten all about them, forgotten all the ancient magics. But how could Phelim, who was only a boy, after all, save the world from all these dreadful monsters? And where could he find the Maiden, the Fool, and the Horse who were supposed to help him? And as Phelim leaves his home and sets out on his quest, the words of the domovoy ring in his ears: 'You are the one. To stop the Worm waking. To do what must be done.' Geraldine McCaughrean is a best-selling author who has won the Carnegie Medal, the Whitbread Children's Novel Award (twice), and the Guardian Children's Fiction Award. "The Stones Are Hatching" is now reissued in a smaller mass-market paperback format.