When mystery novelist and independently wealthy socialite Makoto Masako decides to start a business she settles upon a unique Insurance & Investigation Service. Recruiting a number of beautiful "thrill seeking" amateur detectives, and setting up shop in a fabulous Tokyo apartment/office Masako and company form the "PLAYGIRL(s)" as they affectionately call themselves. Masako and her "daughters" begin investigating various interesting cases and mysteries on behalf of their company`s benefactors. While the bulk of their cases involve solving insurance scams, white collar crimes, fraud, white slavery, robbery and other assorted organized criminal ventures, some of their cases bordered on the bizarre and strange ( i.e. battling ghosts). During the course of their adventures "mother" Masako decides to travel the world and leaves the business in the trusted hands of her "eldest daughters" Tamaki and Masako. Several other "sisters" decide to leave the agency through the course of the series.