Thujwa is a desert city, built from clay and mud, surrounded by walls, secretive, thirsty, and desirous of wealth. But it is also a place of cool breezes, improbably tall towers, plentiful water, bountiful farmland, and vehicles that traverse great distances in a few hundred heartbeats. That is because the Thujwani long ago discovered the secrets of brickweaving: the laying of bricks in special patterns that manipulate the forces of magnetism and gravity. They have used this knowledge to gouge a world of comfort out of the desert, and to enslave others.

Jeppo is a brickweaver but a social pariah who rejected status for love. Nonetheless, Thujwa's highest holy man chooses him to complete a cryptic mission outside the city walls. Joining him will be his new apprentice, a hapless youth named Kulkulla who had washed out in the other guilds. What they find on their trek will only be the first of many discoveries, including the secret of Thujwa's founding, the origin of brickweaving, the nature of the mud-clothed people who speak in a clicking language, and, ultimately, the parts the two of them will play in a centuries-old struggle against injustice.