The Seventh Tower is a series of six books written by Garth Nix, the result of a joint partnership between Scholastic and LucasFilm. The series follows two children from distinctly different societies in a world blocked from the sun by a magical Veil that leaves the world in complete darkness.
Tal is a Chosen from the Castle, and Milla is an Icecarl from the Ice. Together they discover that an evil, long thought to have vanished, once more threatens their world, slowly and secretly letting its presence be felt. A pact was broken, and a war dormant for two thousand years is rekindling. Danger looms, and it is up to these two children and a small band of unlikely heroes to save their Dark World.