Miho and Keisuke, coworkers harboring secret feelings for each other, are both married with families. Though they can't freely meet, they share the same dream: "Just once, we want to forget everything and indulge in sex from morning till night." To make this wish come true, they've spent the past three months planning an affair disguised as a business trip. On the day of their rendezvous, they meet at the station, shed their suits, change into casual clothes, and enthusiastically board the bullet train. Upon reaching their destination, they immediately satisfy their pent-up desire. The intense intimacy they share during this secret encounter binds their hearts even more deeply.