In this post-apocalyptic fantasy, a sea of sand swallows everything except the past. In an endless sea of sand floats the Mud Whale, a floating island city of clay and magic. In its chambers, a small community survives, cut off from its history by the shadows of the past. Chakuro is the archivist of the Mud Whale, meticulously recording the lives and deaths of his people. As one of the short-lived thymia users, he knows his time is limited and is determined to leave a better record than his predecessors. However, the steady rhythm of their isolated existence on the Mud Whale is suddenly disrupted when a reconnaissance team discovers a mysterious young girl who seems to know more about their home than they do…