In her fifth year of marriage, Ayako appeared to be living happily as a devoted wife. But she harbored a secret she couldn't reveal—her failure to repay debts incurred without her husband's knowledge, which led to men arriving to collect, raping her, and subjecting her to intense anal training. Due to these brutal experiences, Ayako's body gradually changed, eventually accommodating thick male fists thrust deep into her anus, culminating in fist fucking. She was no longer satisfied by mere penetration with a cock, but began craving the intense stimulation of powerful fists.