The Secret of Platform 13

Under Platform thirteen 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 has become a horrible rich boy called Raymond Trottle who doesn't understand magic and is determined not to be rescued.
Shortlisted for the Smarties Prize, The Secret of Platform 13 is an exciting magical adventure from Eva Ibbotson, the award-winning author of Journey to the River Sea.
'This kind of fun will never fail to delight.' - Philip Pullman