The Magicians of Caprona - book 2

The Dukedom of Caprona is a place where music is enchantment and spells are as slippery as spaghetti. The magical business is run by two families – the Montanas and the Petrocchis – and they are deadly rivals. So when all the spells start going wrong, they naturally blame each other.
Chrestomanci suspects an evil enchanter; others say it is a White Devil. Or maybe a different kind of magic is needed to save Caprona…