In the Manfuku-cho shopping district, a tight‑knit group of friends has grown up together, each informally assigned a sibling position. Sumiharu, the de facto eldest, is universally praised as a model young man: reliable, considerate, and always ready to help. But this reputation is a carefully maintained facade born from a troubled home life. He has shouldered burdens and responsibilities alone from an early age, convinced that he must be a good child at all times or risk losing the fragile peace around him. That compulsive need to appear perfect hides a deep loneliness and unspoken pain.

Kuzura, the second‑son figure in the group, is the one person who sees through Sumiharu’s mask. Between them lies a history of twisted feelings and a secret that has long remained unspoken. As the story unfolds, the tension between Sumiharu’s desperate performance of normalcy and Kuzura’s quiet, knowing presence forces both to confront the suppressed emotions and unresolved conflict they have carried for years.

The narrative follows the slow, uneasy unraveling of their relationship against the warm, familiar backdrop of the shopping street. While the surface atmosphere of the series can be light and nostalgic, this installment carries a deliberately bitter edge – reflected in the title – as it digs into Sumiharu’s internal struggles and the fragile connection that might finally break or heal. The volume is structured across several chapters, concluding with an extra story, and serves as the final piece within a connected series of standalone works set in the same community.