Annabelle Flynn is the sister of London's two biggest libertines, and her reaction has been to become the picture of purity. But the sensual nature of her family has not been lost on her and she is troubled by urges she dare not follow. She ignores the demands of her body and instead throws herself into two different activities. One is pursuing a proper marriage in Society and the other is trying to save her broken brother by following him into the shocking Donville Masquerade private club run by the unsuitable cad, Marcus Rivers. By night, she inserts herself into Marcus's business ... and eventually she finds herself seduced into his bed.