I have a secret with my wife's best friend, Sumire, that we can't tell our respective partners. Since the day we accidentally met at a bar, we've been continuing an affair. My wife is important to me, but I can't stop this convenient relationship... The situation changed when it was decided that the four of us—our couples—would go on a hot spring trip together. During the trip, Sumire said she wanted to have sex, and I half-believed her. But on the day of the trip, Sumire's husband came down with a high fever, so the three of us ended up going on a one-night, two-day trip...
