Sacred Scars — Kathleen Duey

Sadima, Franklin, and Somiss, driven out of Limòri by a suspicious fire, are living in a cave hidden within the cliffs that overlook the city. Somiss is convinced the dark passages of the caves were the home of ancient magicians, and his obsession with restoring magic deepens. Sadima dreams of escape - for her, for Franklin, and for the orphaned street boys Somiss has imprisoned in a crowded cage. Somiss claims he will teach these boys magic, that they will become his first students, but Sadima knows he is lying.

Generations later, Hahp is struggling to survive the wizards' increasingly dangerous classes at the Limòri Academy of Magic. He knows the fragile pact he has forged with his secretive roommate, Gerrard, will not be enough to put an end to the evil. It will take all the students acting together to have any chance of destroying the academy. Building trust, with few chances to speak or plan, will be almost impossible, but there is no choice.