Ikenai Kozukuri DX ~Kousai Aite no Hahaoya to Ikenai Kozukuri~

Just before summer vacation, protagonist Kengo Terashima is invited to meet his girlfriend Kana Takayanagi's mother, Sayuri. Captivated by her warm smile and curvaceous figure, Kengo falls in love at first sight. While dating Kana, he secretly creates opportunities to be alone with Sayuri, joining her morning runs. One day, while Kana is out, he confesses his feelings and forces himself on her. Though Sayuri resists out of guilt toward her husband and daughter, her long-suppressed desires awaken under Kengo's youthful vigor. Afterward, she tries to dismiss the incident, but Kengo vows to pursue her until she accepts him, plunging them into a forbidden affair.