Mao Kurata and Nana Mi Kawakami were not biological sisters, but shared a close bond as sisters-in-law, teaching at the same school. Their peaceful daily lives gradually twisted due to the disturbing sexual desires of a male student. This student, Ryoh Nishi, appeared to be an ordinary high school boy, but his hidden sadism began to control his actions. As his behavior escalated, the young female teachers were drawn into a whirlpool of jealousy and lust. This shocking turn of events pushed their relationship into deeper, more dangerous territory.