Koyuki is frail and gentle, dreaming of a quiet happiness with her husband. However, her husband was deceived by a guarantor and burdened with massive debt. Facing relentless debt collectors, the couple is approached by the husband's older brother. The brother-in-law offers financial help, but he's an abnormal man obsessed with anal pleasure. At first, Koyuki agrees to cooperate just to repay the debt... But gradually, she's dragged into an anal hell—forced anal stretching, anal masturbation, and double penetration, enduring increasingly intense anal abuse.