Sumire lives alone in her in-laws' old house, harboring deep affection for Ichiro, her husband's older brother, whom she sees like an older brother. She frequently visits Ichiro's home, but one day she is suddenly locked inside a storage shed on the property. Appearing before her is Ichiro himself, standing coldly in her way. As a child, he was locked in the same shed by his mother as punishment, and now, seeing Sumire—who resembles that mother—he harbors both hatred and twisted desire toward her. To confront these buried emotions, Ichiro begins to train and dominate Sumire within the confines of the shed. As past and present collide, Sumire is forced into an agonizing choice. A complex web of human relationships and psychological drama unfolds, stirring intense emotional turmoil.