"One day, when the boy was sufficiently confident in his proficiency with not-evil magic, he ran away from the sorcerer's tower while the sorcerer was out arresting someone. He flew to his family's home in the forest.
His parents were overjoyed to see him again, but he could stay with them only long enough to layer them in magic protections and send them somewhere safer, because the sorcerer was not only evil, but proud and greedy, and the boy knew that he would never allow him to slip his grasp. So he needed to defeat the sorcerer once and for all, and probably the king too for good measure."