Ema has grown tired of her husband's unusual fetishes and increasingly frustrated in bed. When she visits his adult younger brother Yuta, the frivolous man senses the lust she has kept hidden and relentlessly pursues her. She is eventually swept into sex with him and experiences a shattering first orgasm her husband has never given her. Ema tries to dismiss it as a one-time mistake, but her body craves more and can no longer resist Yuta's persistent advances.