After her son spent six months shut away in his room, Kiyoko (Takako Izumi) finds herself emotionally and physically drained, unfairly blamed by her husband for the situation. With no sign of her son recovering, she spirals into despair—until her son's homeroom teacher, Hayami, pays her an unexpected visit. Seeking solace and release from her loneliness, Kiyoko becomes deeply involved in a tender yet fulfilling sexual relationship with him. But that night, her son—having secretly watched the entire affair—explodes in rage and storms into the bathroom.