Polly Adler is a poor Polish immigrant who works in a sweatshop. She loses her job after she is sexually assaulted by her boss, for which her housemates blame her. She then is forced to move out.
Her next apartment is in a building owned by Frank Costigan, a gangster. Frank approves of Polly's attractive girlfriends and pays her to have the ladies go out socially with his friends.
One thing leads to another, and soon Polly is the madam of a bordello. She has genuine feelings for musician Casey Booth, but does not reveal her true occupation to him.
Costigan becomes the top enforcer for mob boss Lucky Luciano and backs Polly's business, which ends up on Park Avenue offering high-class call girls. Casey proposes marriage, so Polly finally confesses what she does for a living. He is willing to overlook it, but Polly feels it is for the best if they part.
