The Secret of Platform 13

A forgotten door on an abandoned railway platform is the entrance to a magical kingdom--an island where humans live happily with feys, mermaids, ogres, and other wonderful creatures. Carefully hidden from the world, the Island is only accessible when the door opens for nine days every nine years. A lot can go wrong in nine days. When the beastly Mrs. Trottle kidnaps the prince of the Island, it's up to a strange band of rescuers to save him. But can an ogre, a hag, a wizard, and a fey really troop around London unnoticed?