The Ogre of Oglefort Eva Ibbotson

When a Hag, an orphan boy and a troll called Ulf get sent to rescue a princess from an ogre, they expect it to be a fairly standard magical mission. But the ogre is depressed, the princess doesn’t want to be rescued – and the ogre’s dead wife is turning in her grave. The Norns who rule their fates decide to take things in hand – will the Ogre meet a bloody end, or will he get a happy ending?