Aya raised her only daughter, Minayoi, by herself after her husband passed away when Minayoi was young. Minayoi has grown up and has a boyfriend. Her boyfriend is the second generation of a sake shop and a very easy-going young man. Aya was very happy that her boyfriend was her daughter's boyfriend. However, there was a hidden face to that young man... He was so virile that he had a strong dick. One day, Aya was shown a standing dick by the young man. "How can I be attracted to my daughter's boyfriend's dick?" Aya desperately tried to keep her reason. However, her instinct destroyed her reason. What decision did Aya make when she couldn't stand it anymore?