Under Platform 13 at King's Cross Station there is a secret door that leads to a magical island...
It appears only once every nine years. And when it opens, four mysterious figures step into the streets of London. A wizard, an ogre, a fey and a young hag have come to find the prince of their kingdom, stolen as a baby nine years before.
But the prince they find is a horrible, spoiled young boy who doesn't understand magic. Could this spell disaster for the creatures of the Island of Mist, or is it a terrible case of mistaken identity?