Yuka, a true masochist, wants nothing more than for her oh-so-kind boyfriend, Mahiro, to torment her. Mahiro, who declared he’d become a sadist for her, tries his best to be dominant for her as they celebrate milestones like birthdays and their first trip together. However, it becomes apparent that Mahiro is struggling with something. What could it be? And could it have something to do with the mysterious woman, Yukino, who shows up at his workplace?