Under the pretense of tutoring, a middle-aged man subjects the twin sisters, Kasumi and Mitsuki, to obscene discipline sessions. Despite their initial facade of seriousness, Kasumi’s diabolical nature and Mitsuki’s clumsiness make them difficult students to manage.
As the tutor uses every trick to keep the sisters under control, the twins resort to do all kinds of pranks to get rid of him. He was on the verge of being fired. However, Kasumi is ultimately forced to perform lewd roleplay while enduring the acts that leave her desperate.
Determined to protect her clumsy twin sister, Kasumi makes the self-sacrificing decision to be the only victim of the tutor’s twisted pleasures. She finds herself vulnerable to his desires while slowly giving in to the pleasure.