Kashiwagi Natsuko, who has stayed in the US for a long time, is a new investigator of Adjust Research, an insurance investigation firm. She possesses scientific genius and vast personal wealth, but has a tendency to feel out of place in Japanese society which is overly logical. On the other hand, Tono Aki is a veteran investigator in the same company. Born in the old part of Tokyo and a former delinquent, she is rather stingy because she lived in poverty when she was growing up. However, she has superb memory and animal instincts. Natsuko and Aki make an odd combination as they confront ingenious crimes associated with insurance money and expose the truth.