On the remote island of Utashima, a young woman named Orin works as a fisherman. Having once lived in the city, she has since returned to her island home, settling into a peaceful life surrounded by the sea and her friends. This quiet existence is disrupted by the sudden arrival of a mysterious man, whose presence creates ripples through the calm community. The story follows the changing dynamics between Orin and this stranger over the course of a summer, exploring how their encounter gradually alters her life on the island. As tensions and connections deepen, the narrative leads toward the end of the season, with the title signifying the conclusion of their shared summer. The manga spans five volumes, beginning with Orin’s established island routine and building through the man’s arrival, the ensuing emotional developments, and the eventual resolution of their summer together.