Turns out our class has to read the first three books in the Earthsea quartet, and The Tombs of Atuan is the second. I loved this book, I like it much better than A Wizard of Earthsea (though, credit goes to Le Guin for creating a wizard who screws up big time and has to deal with the ramifications - I love when cliché is avoided!) It also won a Newbery Medal in 1972. Unlike A Wizard of Earthsea, which details the story of a wizard on an epic journey to confront his 'shadow', The Tombs of Atuan is a story of reaching freedom.
A 5 year-old girl is taken form her family because she is found to be the reincarnation of the high priestess in the service of the Nameless Ones. She is heir to the tombs of Atuan where the Nameless Ones dwell. The tombs become a refuge for her, and she is the only one allowed in the labyrinth below, which holds treasure. Ged comes to the tombs looking for the long-lost half of the ring of Erreth-Akbe, but men and light in the tombs is sacrilegious. But Arha is lonely and spares his life. The king's priestess finds her out and Arha has a false grave dug to clear her name. Ged finds the ring and relates the the Nameless Ones are real, but they are dark like his shadow. Ged tells her her true name - Tenar. As the pair try to leave the tombs, there is an earthquake, and the king's priestess is killed. Tenar and Ged now have the Ring of Erreth-Akbe with the power to restore Earthsea to peace.