In an endless sea of sand drifts the Mud Whale, a floating island city of clay and magic. In its chambers a small community clings to survival, cut off from its own history by the shadows of the past.

The Mud Whale is in dire trouble. In four days, the imperial apátheia soldiers will return to destroy it and its inhabitants. But the Committee of Elders would rather kill everyone on board than wait for the "mercy" of the empire, and the fighters of the island will do the elders' bidding without a second thought. Now Chakuro and the other children are forced by circumstance to rebel against the adults in order to save their home and their lives.