Yuuya has liked Koko since elementary school. Recently, they reunited by chance, and after mustering the courage to confess, they started dating. As it turns out, Yuuya's father is a teacher and had once been their homeroom teacher. Yuuya brought Koko home and introduced her to his father as his girlfriend. However, Yuuya didn't notice his father's lecherous gaze fixed on Koko's well-developed breasts. Yuuya's father summoned Koko under the pretense of discussing something about Yuuya. Believing innocently in her former teacher, Koko listened to him, but he spiked her drink with an aphrodisiac and forcefully pushed her down.
