The manga (also known as Marriage Exchange: The Night of No Return ) is an adult-oriented series that explores the complex emotional and physical boundaries of two married couples who have been close friends since their student days.
The story heavily focuses on the psychological switch from "boredom" to "excitement" caused by jealousy. Seeing one's spouse with another person awakens dormant passions in some characters, while destroying trust in others. fuufu koukan: modorenai yoru manga