Asahi and Oshima, who work in the same office, are in an adulterous relationship, secretly desiring each other's bodies when no one is watching. Both have families and cannot meet freely, but they share the same desire. "Just once, I want to forget everything and devote myself to sex." To make this dream come true, they planned an adulterous trip in the guise of a business trip several months ago. On the day of the trip, the two meet at the station, change from their suits into casual clothes, board the express train, and as soon as they arrive at the inn, they passionately kiss each other...