Castle - Garth Nix

Second title in fantasy adventure series, THE SEVENTH TOWER, from bestselling author, Garth Nix. In the Dark World, society is ranked according to colour clans and the most precious commodity is light. In all the world there is only one place that ever sees the sun, a seven-towered castle on a mountain high above the desolate ice lands below.

Tal, a Chosen, and Milla, an Icecarl, have been thrown together on a dangerous quest to gain a Sunstone. They must reach the Castle of the Seven Towers, home for Tal, but a dangerous and strange place for Milla.

From the deadly Hall of Nightmares to the magical chambers of Tal's great-uncle Ebbitt, they must navigate the Castle without being discovered. Sinister forces are conspiring against them and it will take all their strength just to survive.