Midori (Noriko Hamada) is a 40-year-old married woman stuck in a dull, passionless marriage with a distant husband. Her life shifts drastically when her daughter, Maya (Nana Nanaumi), brings home her prospective marriage partner/fiancé, Matsushita (Keisuke Tarumi), who also happens to be a junior colleague at Midori's husband's workplace. Intrigued and sexually drawn to one another, Midori and Matsushita begin a passionate, secret affair. Their clandestine physical connection escalates into an intense, taboo romance, shattering familial boundaries as Midori deceives both her husband and her daughter.