Ai, a member of the Special Fraud Investigation Unit's First Division, begins working at a snack bar used for business meetings in order to make contact with the notorious "land scammer" gang. After one month, she finally obtains a lead on the group's activities. The next step is a plan to go undercover as the proprietress of "Yukawaya," a long-established hot spring inn. As the investigation reaches its final stage involving a 10 billion yen deal, the developer who appears on the scene turns out to be none other than Ai's own husband. With crucial evidence in hand and unexpected family ties now involved, the case takes an even deeper and more complicated turn.