After divorcing her husband, Maki began living alone in Tokyo when she suddenly received a message from her long-lost son, Shinkuro, informing her of her ex-husband's death in an accident. Worried about her son's well-being, Maki travels to Shizuoka. However, upon reuniting after ten years, Shinkuro confronts her with harsh words, calling her the mother who abandoned him. Overcome with confusion and overwhelming guilt, driven by a desperate need to comfort him, Maki begins to support Shinkuro with her own body. Is this an act of atonement, or twisted devotion? Set in a quiet onsen town during a summer season, this story delves into the depths of emotion, portraying a distorted bond and forbidden encounter between mother and son.