The Secret of Platform 13 is a sprightly fantasy with a sly edge, at once sweet and tart.

Under platform 13 of King's Cross railway station in London is a "gump," a doorway to a marvelous island kingdom where humans and magical creatures coexist happily. The gump opens once every nine years for nine days only, so the decision to pass either way through it is not one to be taken lightly.

One year, the gump's opening is marked by a terrible event. Mrs. Trottle, a wealthy and not very nice woman, desires a child but does not seem able to have one the usual way. When her attempts to adopt a baby are foiled, she takes an opportunity to steal the island's infant prince from his nursemaids who brought him with them when they went to visit their old home in London.

Nine sorrowful years pass, after which a group of rescuers is assembled to go through the gump and rescue the prince. They are a curious quartet: a one-eyed giant named Hans who wears lederhosen and spends his time herding goats and making cheese; Cornelius, an elderly wizard; Gurkintrude, a fey with a knack for inspiring vegetation; and Odge Gribble, a young hag who is not very hag-like -- but she's working at it.

The four emerge into London and with the help of the ghosts who hang out in the deserted train station, they find the prince, now known as Raymond. He's not at all what they expected -- in fact, he is just about as beastly as Mrs. Trottle. The rescuers are disappointed; they far prefer Ben, who lives with his grandmother and works among the servants at Trottle Towers.

But their orders are plain, and they set about the task of convincing Raymond to return to his true home. They call on the magical creatures remaining in London for help, knowing it will be a daunting task. Little do they know just how difficult it will be!

Ibbotson's tale is fresh and appealing, sort of like Road Dahl without quite so much bile. She puts a unique spin on her characters: harpies with immovably and impeccably coifed hair and sensible handbags, Mrs. Trottle and her signature scent called "Maneater," stubborn and forthright Odge whose only claim to hagdom is her blue tooth. Also featured are the mistmakers, sweet, seal-like creatures who emit mist from their mouths then they hear music, with the result that the mist conceals the island.

The plot is suspenseful, with the band of rescuers' reluctance to install the odious Raymond as their prince hampering their effort and adding to the tension. The humor is on the dry side -- not a complaint, for most of the 8- to 12-year-olds for whom the book is intended will be able to appreciate it. The Secret of Platform 13 works very well as a read aloud and is sure to appeal to readers of all ages who appreciate creatively written fantasy.