Noticing his wife's exhaustion from parenting, Kazuki seeks sex and visits a love hotel, only to find Kana—the beautiful mom from his son's class—there. Awkward at first, Kana softly whispers, "Our little secret?" as she opens her body to him. Despite guilt, the thrill and taboo of being pleasured by his wife's close friend overpower his conscience, driving him back to the love hotel to explore a new, forbidden relationship.