No.1 Bestselling Series from the Blue Peter Award winning author of How To Train Your Dragon. Enter a land of wizards, warriors, mythical creatures and powerful magic in an exciting new fantasy adventure."Do not be afraid, dear trees," implores Crusher the Giant as he strides through the forest ... while up above, the Witches sharpen their talons in readiness. The third electrifying book in The Wizards of Once series fizzes with magic and introduces us to a host of glorious new characters - bears and piskies and magical pins and needles to name but a few. Xar and Wish are heroes with a huge task ahead. Confronting the Nuckalavee is not for the faint hearted but with Magic and Iron together, surely they will prevail. Stunningly written, magnificent in scope, hilarious and thrilling, Knock Three Times immerses you in a world you won't ever wish to leave.