Found

In the third adventure of the Magic Thief, Conn is following a shooting star through a wilderness of woods and mountains, far from his home. He thinks the star will lead him to his locus magicalicus, or wizard stone. He needs this to save his city of Wellmet, whose magic is close to dying. With a new order of exile from Wellmet, this time with a death penalty, Conn has never been in such a tight fix.