Rosa lives in a world where she discovers there is magic. It arrives with Balthazar, a large black cat, just when she needs it most.

Even so, it takes all her courage to stay hopeful and adventurous when her dreadful aunt and uncle move into her life. And when she finds herself abandoned in the ancient city of Venice, can magic help her then? Perhaps it can. The stars are watching, and there are lots of cats in Venice .