During gym class, Nana's stiff body and particularly poor posture stand out. Concerned about the risk of injury and negative effects on her development, the teacher decides to provide special after-school instruction. First, he binds her hands behind her back to release tension in her shoulders and arms. Next, he ties her ankles, adjusting the muscles throughout her body. Nana receives no explanation, left confused and frightened as the session progresses. Finally, a vibrator is attached to her groin. As the small toy trembles, Nana experiences both fear and pleasure, her body growing more flexible with each pulse.