18+ Naka●shi Shimai no Hen●i Kiroku

The story follows Akiho Niido, an 18-year-old college student leading a fulfilling life, except for her unemployed sister, Kana, who is staying with her. Akiho struggles to manage her sister's untidy habits. Their situation takes a turn when Chibusa, a busty woman identifying herself as a debt collector, visits them. She informs Akiho that Kana has accumulated a debt of 3 million yen. Unable to repay the debt, Chifusa offers them a "Problematic Part-Time Job" in exchange for a high pay. The job's details remain confidential, leading to a slightly erotic work comedy about two sisters entangled in a peculiar debt.

(Source: Bushiroad, translated)