START-331 A perverted couple with a swapping hobby planted an NTR fetish in them! A pure and innocent commoner wife is lent to a rich couple and becomes immersed in immoral pleasures.

The Kominato couple, who have just moved, hit it off with the couple living next door in a luxurious mansion. Despite being newly married, the husband, Yuzuru, has erectile dysfunction and is sexless. When he is invited to swap partners by their neighbor, Atsushi, he awakens to his cuckold fetish. The couple train the innocent and naive Yotsuba to become a pervert who enjoys sex with other men’s dicks, sinking her into the swamp of immorality…