Misaki and her husband have been married for seven years, her husband is 20 years older than her. Even though he is 50 years old this year, her husband is still fascinated by Misaki's body. Even though he wanted to be, because he is old, Misaki's husband quickly "surrendered" even though she had not yet reached orgasm. The two also promised to always be honest with each other about anything, and she kept that promise until one day... Hayato was her husband's neighbor when they were children. Because Misaki's husband is much older, the two always considered each other as real brothers. Hayato often came to eat at Misaki's house three times a week. However, Hayato's true intention was not simply to eat with his "older brother". He had always had feelings for Misaki, but she did not realize this. Once, when he accidentally asked Hayato if he had a girlfriend, Hayato gathered all his courage to confess to her. Misaki just thought Hayato was joking and wanted to let this matter go. A few days later, when she came to get documents from Misaki, Hayato suddenly attacked her. Even though Misaki was resisting, Hayato still realized that she was enjoying this very much. And just as he thought, this was the first time Misaki lied to her husband. If she told the truth, everything with Hayato would end, but for some reason she couldn't do that. And so, she continuously let Hayato fuck her, even Misaki took the initiative to seek him out. Her husband also suspected, but because Misaki kept lying, as well as because she trusted his wife too much, the "adulterous couple" continued to have an affair right behind his back...