What is Tanpo? It's basically a security measure where something valuable is used as collateral. In this particular tale, the Suzumiya family finds themselves drowning in debt and decides to pawn off their three daughters, Yukari, Ai, and Midori, in exchange for the money they owe. However, they mistake a worthless individual named Ishihara Yuujirou for the Daikoudan Group. Unfortunately, the family and staff coerce Ai-chan into using her body to convince Yuujirou to have sex with her in order to secure the money needed to pay off their debts.
Additional one-shot:
Volume 6: I Just Want to Call You Big Brother
