The day that Leo Zifkak became the owner of the music box, his life changed forever.

Leo didn't know this at the time. His heart didn't miss a beat as he took the box calmly from his mother and put it on his desk. He had no idea what he was holding in his hands.

The old music box has its rules, carefully handed down through the generations in Leo's family. A long-ago ancestor called Rollo had brought it back from one of his world trips. It had a plain black shiny lid, but its sides were painted with detailed scenes of a town, a castle on a hill, a queen in a long blue gown.

Those who had owned it before Leo understood its powers well, and placed strict limits on its use. But now it is Leo's music box, and although he respects the rules, his least favourite cousin Mimi Langlander does not.

When the rules are flouted and the Blue Queen appears and takes Mimi's dog Mutt back to the world of Rondo, Leo finds himself on an alarming quest to retrieve him, with the disagreeable Mimi at his side.