The old music box, with its strict rules, has been carefully handed down through Leo's family for hundreds of years. Painted scenes of villages, mysterious forests, a castle on a hill and a queen in a long blue gown decorate its sides. An astounding secret is hidden beneath its gleaming black lid. 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 broken, Leo's ordered life is changed forever as he and Mimi plunge together into a thrilling quest in the fantastic world of Rondo.