I have a secret that I can't tell my wife's best friend, Sumire, and each other's partners. - She continues to have an affair as she is swept away from the day she meets by chance at a certain bar. My wife is important, but it's a convenient relationship that can't be stopped. The relationship changed completely when the four of them decided to go on a hot spring trip. I was skeptical about Sumire's story that she was going to have sex during the trip, but on the day of the trip, Sumire's husband had a high fever and the three of us decided to go on a trip for 2 days and 1 night.