Itsunori falls at first sight for his coworker Karin Kitaoka at their pre-employment ceremony and wins her over with an intense courtship. After joining the company they are assigned to different departments, and Karin's sales job brings frequent drinking parties and social events. His fears that she might cheat or be sexually harassed twist into an NTR fetish: he wants to watch his precious girlfriend be taken by another man. Unable to suppress the desire, he chooses a younger university acquaintance to seduce her.