Hiroki, who has been married for five years, is a little worried about his wife's drinking habits. At that time, he happens to come home at the same time as Yuri, who lives nearby, and they start talking. At first, they mostly just talk about trivial things, but before long, they start talking about their marital relationships, and they even start venting their frustrations to each other about their home lives. Yuri's husband started working night shifts, and their relationship got worse and they became sexless. Although they were just venting their frustrations, for some reason Hiroki's heart felt lighter. Just then, Yuri suddenly sends him a selfie video. Hiroki is confused and bewildered. But he is also excited. And finally, he accepts Yuri's invitation. Hiroki has never cheated on his wife since he married her. He is conflicted, but he goes to hear Yuri talk. And then he and Yuri start having an affair. Hiroki is obsessed with Yuri's charms, even though he thinks he should break it off. After this relationship continues for a while, a strange phenomenon begins to occur. It is...