The Tombs of Atuan (Earthsea Cycle, Bk. 2)

When young Tenar is chosen as high priestess to the ancient and nameless Powers of the Earth, everything is taken away from her - home, family, possessions, even her name. She is now known only as Arha, the Eaten One, guardian of the labyrinthine Tombs of Atuan, shrouded in darkness. When a young wizard, Ged Sparrowhawk, comes to steal the Tombs' greatest hidden treasure, the Ring of Erreth-Akbe, Tenar's rightful duty is to protect the Tombs. But Ged also brings with him the light of magic and tales of a brighter world Tenar has never known. Will Tenar risk everything to escape the darkness that has become her domain?