A lone landmass, named the Mud Whale, sits amidst an extensive stretch of sandy terrain. The land is inhabited by a community of "Marked" individuals, gifted with supernatural powers but a limited lifespan due to their ancient origins. Chakuro, the archivist of the settlement, constantly explores new lands, but only comes across deserted and abandoned territories. One day, a new landmass emerges on the horizon after six months. Chakuro and their crew embark on an exploration mission, only to stumble upon remnants of a long-forgotten civilization buried under ruins. Amidst these ruins, Chakuro encounters a girl whose very existence will determine the fate of the Mud Whale for all eternity.