Southern girl Mary Carlton finds out that her brother, Bob Carlton, is going to the electric chair for a crime he says he didn't commit. In order to get her brother exonerated, Mary travels to New York and pretends to be a Chicago gun moll. She wins the love of two gangsters, Handsome Joe and Big Steve Drummond. Joe, it turns out, isn't a gangster at all, but an undercover detective. He attempts to help Mary prove her brother's innocence, and the two of them are caught in a fierce gun battle between the crooks and the cops. They make it through alive (although Drummond gets his due), and Bob is released at the last minute.