Sisters' Debt / Debt Sisters

Kasumi works as a teacher at a private academy. One day, a stranger comes to her and, demanding to repay her father's debt, tries to persuade the heroine to have sex. One of her students, Okura, comes to Kasumi's aid and drives the stranger away. Okura offers his teacher money to pay off her father's debt, but Kasumi refuses. Fearing that she will again fall into the hands of dirty extortionists, Okura decides to buy Kasumi herself and pay her money for sex with him...