The story follows Asai Saki, a seemingly strict public morals officer with hidden desires. She engages in an explicit escapade with the protagonist, revealing her true nature. Despite her public morals role, Saki's deviant desires continue to escalate leading her seek pleasure from other... sources. The plot takes unexpected turns as Saki's sister, Shiki, finds out about Saki's relationship. Shiki, eager to lose her virginity, strikes an "unique agreement" with Saki. Consequences arise when Saki and Shiki's mom discovers their actions, causing an incredulous scenario to unfold...