This is an adventure story about Ah Shu and Ah Lang. Ah Shu is the executor of the mission, and Ah Lang is the intermediary of the "Task Association," specifically looking for tasks for Ah Rat. While the two were constantly completing various difficult tasks, Ah Shu revealed his yearning for something indescribable – "The Sea of Stars"; while Ah Lang was also looking for clues to the disappearance of the family during various tasks. The two learned from the mission that in addition to the present world, there is an "upper world," and various signs indicate that Ah Shu's yearning and the clues Ah Lang is looking for point directly to the "upper world," even "more upper world."

Through their continuous adventures, they gradually learned that no matter which world, they cannot escape the fate of the tipping point of entropy.