The main character, Minami Shirou, makes his living collecting debt money at Hokuyo Finance. He takes a cab to a residential area where the person who owes money lives. Shirou is rather fond of this business. Perhaps it is because it goes well with his inherently serpentine nature.
Above all, there was a perk to this business. When the debtor was a woman, they often use their bodies as a weapon to woo him. He takes advantage of his position to make the women into his sexual prisoners.

The debtor in question stopped paying three months ago. He also disappeared three days ago. Only his wife and child still live in the home and there are no signs that he is coming back. Shirou checks every day to see if there are any signs that the debtor has returned home or if the family is planning to run away at night.

Shirou goes up to the home and rings the bell. The woman answers and Shirou is surprised. As he looks at her he discovers that the woman is Hitomi, a former gravure idol. She was the object of his lust and used her as masturbation material when he was a student. The first thing that came to mind upon this discovery is not the debt or the whereabouts of her husband, but her body.

Someone else in the neighborhood, Nagamine Rumiko, the sex-starved mother notices these encounters and it piques her interest in Shirou.

[Translated from the official website]