The story centers on a Kargish child who is taken from her family and dedicated as the high priestess in the service of the "Nameless Ones" on the island of Atuan. Her true name is Tenar, but she is renamed Arha, "the eaten one", when she is formally consecrated to the gods' service at age six, as all the high priestesses are considered reincarnations of the first.
Tenar's youth is a haunting contrast between lighthearted childish escapades and dark, solemn rituals. Gradually she comes to accept her lonely, anonymous role, and to feel at home in the unlit underground labyrinth, the eponymous Tombs, where the malevolent, powerful Nameless Ones dwell, and where prisoners are sent for a slow death. Indeed, as she becomes aware of the political machinations among the older priestesses, the Tombs become a refuge to her, as she is the only one who may freely move through the labyrinth under them.
Ged, the protagonist of A Wizard of Earthsea, meets Tenar when she is fifteen years old. He comes to the Tombs in order to find the long-lost half of the Ring of Erreth-Akbe, a magical talisman necessary for peace in Earthsea, which had been broken centuries before. (The other half has come into his possession, though it takes a dragon to inform him what it really is.) Arha finds him wandering, lost in the magic-laced labyrinth, and traps him underground to die in order to punish what she sees as sacrilege. She goes back and forth in her mind as to whether she should kill him. Yet in her loneliness, she is drawn to him and listens as he tells her of the outside world.
Tenar is eventually won over by Ged's kindness. She realizes that the Nameless Ones demand her service, but give nothing and create nothing in return. Ged must expend his strength continually on hiding himself from the Nameless Ones, as they would kill him if they detected his presence. She helps him escape from the Tombs with the other half of the ring, as he frees her from the priesthood. The Tombs fall in upon themselves as Tenar and Ged escape."