Stonefather — Orson Scott Card

When Runnel, a friendless peasant from a village so humble that money is a new concept, leaves his mountain valley, he is completely unaware of his magical talents. Seeking his fortune, he stumbles into a centuries-old feud when he travels to Mitherhome, the city of the water mages. He accepts a servant''s position in the household of the sole stone mage permitted within the city walls, and there his untapped magical talents and his fascination with his master''s abilities are a predictably dangerous combination. Soon, without meaning to, he complicates and endangers the lives of everyone he has come to know and care about, for when it comes to magic, there are rules and laws, and the untrained mage-to-be must be careful not to tap into deep forces and ancient enmities. Otherwise, other people might end up paying the price for his mistakes.