In order to help her rebellious niece Hikari, Aki asks her brother to send her some restraints like handcuffs and ankle cuffs. When she uses them on Hikari, the girl tries to escape but fails miserably. The next morning, Hikari wets herself while trying to use the bathroom due to constipation. As she changes into dry clothes, Aki notices that her panties are soaked in something other than urine - it's clear evidence of anal leakage caused by excessive masturbation. Despite refusing food constantly, Aki forces-feeds her until she cries out for mercy; then proceeds to spank her hard enough make tears flow freely. Eventually, after about a week or so, Hikari starts opening up emotionally but still struggles with her enema fetish which leads to frequent accidents during sleep time when wearing diapers (omutsu). When Hikari complains about stomach pain due to constipation again one day, instead of giving medication, Aki decides try manually removing feces using anal stimulation techniques learned online. This proves successful initially but ends up causing involuntary defecation midway through process because of heightened sensitivity caused by prolonged arousal earlier on. To teach her lesson without making things worse physically or emotionally, Aki decides punish her further by having her kneel down while slapping her ass repeatedly until she finally admits guilt and apologizes sincerely for all transgressions committed against both family members involved directly or indirectly throughout entire ordeal thus far...

訳アリの姉から、姪・ひなのの面倒を見るよう頼まれた。ひなのは反抗的で、早々に家出を企てたので、首輪と手錠で自由を奪った。その翌朝、ひなのはトイレに行けずオネショ。濡れた下着を替えていると、股間がオシッコではない粘液で濡れていた。食事を拒否し続ける彼女に、強●的に食事を与える。あまりにも聞き分けがないので説教し、泣くまでビンタ。感情の高まりとともに性欲も高まってフェラさせる。一週間ほど経った頃、ひなのも心を開き始めた。しかしオネショ癖は治らず、就寝時はオムツを着用させた。ひなのが便秘で腹痛を訴えるが薬は無い。摘便を試みると、ひなのは肛門刺激で感じてしまう。刺激を続けると尿意も高まり、オシッコを漏らしてしまう。膝に乗せお尻を叩き反省させる。半月も経つと、ひなのは学校にも行けるようになった。オムツで出掛けるご褒美に、ひなのに耳と尻尾をプレゼントする。アナルプラグが付いた尻尾に、彼女は激しく感じてしまいオモラシ。オモラシおむつで肉棒を包んで手コキさせた後でフェラさせる。