Old magic breaks loose in modern London to rescue a kidnapped prince in this droll, if formulaic, farce from Ibbotson. When wealthy Larina Trottle decides she wants a child, she snatches the first baby that comes along, leaving distraught royal parents on the other side of an ancient gate (Platform 13, in an old Tube station) that opens once every nine years. Nine years later, through the gate comes a rescue party: an invisible giant, a very old wizard, a fairy, and a young hag-in-training, Odge Gribble. But Raymond Trottle is a fat, selfish, greedy, stupid, thoroughly spoiled child. Reluctantly, with the help of the Trottles' thoroughly likable kitchen boy Ben, the rescuers set about their task, without reckoning just how difficult crafty Larina is going to make it. Ibbotson strews her tale with magic creatures and stock villains, including bodyguard/assassin ""Soft Parts"" Doreen, armed with deadly knitting needles, a terrible lake monster who gives a delicious new meaning to the term ""clear skin,"" and a band of harpies, horrible to behold in pearls, tight perms, and stretch tops. At the very last moment comes the revelation that Ben, not Raymond, is the true prince, and Odge engineers the happy reunion. With scrawled, comic black-and-white drawings by Porter, it's not exactly Roald Dahl, but Ibbotson is at least a distant cousin.