A magic spell whisks Philip away to a far-off island, where he meets the beavers, Mr Edgar and Baby B. All the other animals have been imprisoned by the wicked witch Oyin in the dungeons of Beaver Towers, and tomorrow night she will put them to death and take over the island. Only magic can save them now, but Mr Edgar's vital spell book is locked away in Beaver Towers. Philip sets out at dead of night on a perilous mission - into the witch's stronghold ...