Yui, a married woman who cannot be satisfied by her prematurely ejaculating, submissive husband, and Nono, a married woman who is fed up with the persistent sex of her husband who has a delayed ejaculation. The couples who live next door to each other in an apartment building each have their own sexual problems. One day, Yui and Nono get a free hotel stay voucher from a newspaper salesman and come up with a plan. The plan is to swap couples using two rooms connected by a door. And on the day that the two couples' NTR doors are connected...