Mari has married her husband, who is also a teacher, and has started a family. During a happy family get-together, her face stiffens when her husband mentions her name. It is her former boss, who nurtured her as an educator when she was new to the profession, and he is using her as his plaything, taking advantage of their past relationship. Even though she rejects it in Kokoro, his hands, which know her sensitive spots so well, bring her to climax. Carried away by feelings of guilt towards her husband, Mari continues to indulge in the pleasure lessons that she cannot resist today...