My mother, who has a strong sexual desire (has a habit of cheating), cheated on her beloved boyfriend.

It's been a year since I started dating. Shinya was invited to her house for the first time, and was so nervous that she arrived earlier than planned. I pressed the intercom timidly, and it was her mother Yu that greeted me, not her. The two of them just waited together for their girlfriend, who had just gone shopping. Shinya can't help but be curious about Yu, who exudes a naughty, adult sex appeal. When Yu notices Shinya's gaze, she ends up seducing her with her determination...