Mito and Yamagishi live in the same neighborhood. Once a month, they will organize a home party together and drink together and talk about life. But a few days later, Aika got into an argument with her husband and she wanted to go back to her mother's house. Kana kept advising and letting her stay at her house to have a second thought. At the same time, Aika's husband had a high fever, and Kana stayed at Aika's house to take care of Aika's husband. And Kana's tenderness touched Aika's husband and because he hadn't had sex for a long time, he couldn't help but take her over. Kana's husband witnesses it through the window, and he decides to make love to Aika for revenge. Not stopping there, he forced his wife to have sex with him right in front of him, so that he would also have sex with Aika in front of that husband to take revenge. But it seems that they are gradually immersed in the stimulation of having sex together, so the relationship gradually becomes closer and later, once a month, they will have sex together to make everyone's relationship closer...