The male protagonist and the female protagonist are neighbors. The male protagonist has a fiancée and they live together. The female protagonist and the male protagonist's fiancée are good friends.

The male protagonist and the female protagonist are neighbors. The male protagonist has a fiancée and they live together. The female protagonist and the male protagonist's fiancée are good friends and she gives her advice on how to have a relationship with the male protagonist. The three of them go out to the hot spring together. At night, the male protagonist and the female protagonist have sex. Later, the female protagonist doesn't want to affect his relationship with his fiancée and wants to pretend that nothing has happened. The male protagonist is very angry. In the end, the male and female protagonists are still together.