"The evil female counterparts of the Hardy Boys, the Sisters Noir, and their equally evil father return to create serious chaos! Joe and Frank are working out at a top-secret training facility on the grounds of A.T.A.C. headquarters when the compound is set-upon by Poppa Noir's anti-justice organization. The only two people who are available to free the captured adult ATAC agents are the Hardy Boys, and they have their hands filled battling their opposite numbers, the Sisters Noir!" -- from publisher's web site.