When Thomas Applegate is cheated out of his marble collection, he pops in to see Mr Armitage, the owner of an old junk shop, to buy some more. But he gets more than he bargains for when he finds and washes an old purple-and-ivory marble that was hidden in a broken Chinese vase. It is the start of a magical journey back to ancient China, and the rescue of a Chinese princess and his new-found magician friend, Wing Ling.