She, who embodied the ultimate navel torture in Z-18, returns with fierce determination to relentlessly grind and torment only the navel. Right after filming begins, she's knocked down instantly by an unexpected blow, depicted perfectly on screen—the moment a serious kick lands is a must-see. Her sheer dread and desperation radiate through her expressions and movements. The fact that while abdominal muscles can be trained, the navel itself cannot, highlights its vulnerability and further enhances the appeal of this work.