In a vast desert world, amidst the sea of sand, the Mud Whale island sails, home to a town where most are 'Marked' with powers that come with a fatal price. Chakuro, the youthful archivist, delves into chronicling the uncovering of new isles, all deserted like the ones before. A fresh island emerges after six silent months, prompting Chakuro and his comrades to investigate. Amidst the ancient ruins, a girl is found, altering Chakuro's fate and reshaping the Mud Whale society.