Hoshikuzu to Hatsukoi Hyaku-nen sou Monogatari

As a child, Yuuri was sent to spend the summer at Century Manor, the home of his grandfather, and met a boy who taught him origami and promised to write to him. Years later, now 18, Yuuri returns to the manor and meets his cousins Yamato and Asao. As he settles in, he feels a sense of familiarity with Yamato and discovers origami in one of the rooms, stirring memories and emotions tied to the house.