Lost

In The Magic Thief: Lost, the second book in Sarah Prineas's acclaimed middle grade fantasy series, wizard's apprentice Conn is forced to improvise after he loses his locus magicalicus--with explosive results

Never mix fire with magic

Conn may only be a wizard's apprentice, but even he knows it's dangerous to play with fire . . . especially around magic. His master, Nevery, warns him that it could all blow up in his face. Besides, they have bigger problems to deal with. There is evil afoot in the city of Wellmet, an evil that isn't human.

But Conn is drawn to the murmurs he hears every time he sets off an explosion--something is trying to talk to him, to warn him. When none of the wizards listen, Conn takes matters into his own hands. His quest to protect everything he loves brings him face-to-face with a powerful sorcerer-king and a treachery beyond even his vivid imagination.

Diana Wynne Jones, author of Howl's Moving Castle, praised this middle grade fantasy series filled with magic and wonder, saying of the first book: I couldn't put it down. Wonderful, exciting stuff.