After two centuries of feuding the powers of the two families of magicians in mythical Caprona are too weak to stop an incipient war, but the younger members of the families find a way.
Gwendolyn Chant and her brother Cat find the Chrestomanci Castle family's magic powers difficult to counter with the inferior power of the Coven Street witches.
Tonino is the only person in the famous Montana household who wasn't born with an instinct for creating spells, but he has other gifts. His ability to communicate with cats just might help defend the city of Caprona against a mysterious enchanter -- but only if Tonino can learn to cooperate with a girl from the hated Petrocchi family of spell-makers.