A defense attorney for a mob boss becomes district attorney and prosecutes his old boss.
In his gambling club Vanny Powers (William 'Stage' Boyd) offers his attorney Tom Cardigan (John Barrymore) $5,000 to defend one of his female renters in night court for tapping on a window. During a raid a policeman tells Cardigan to use the fire escape. Cardigan whispers to the female judge and says women are more sacred than the law. The gambling crowd is sentenced to $50 fines, which Powers pays. After putting a ring on the finger of June Perry (Helen Twelvetrees), he tells the story of his mother to get her off. Cardigan brings June home, kisses her, and offers her a drink. She can stay there while he collects from his boss. June removes the alcohol from the place, because she wants him to be great. Vanny is shot by Bird Legs Duffy, and Cardigan visits him in the hospital. Vanny tells Cardigan to take a job with the district attorney, saying he could be governor someday. Cardigan warns him he will be changing sides.
Cardigan visits the district attorney Ulrich and soon has the job himself. June warns him to watch out for Powers. Cardigan prosecutes Nora Dean (Mary Duncan) for murdering her husband by bringing the bed into the courtroom and getting her to confess on the witness-stand. Vanny visits June looking for Cardigan and asks him to squash the Decker indictment, but Cardigan refuses. Vanny threatens to tell of the burglary that sent Cardigan to reform school. Ulrich's daughter Lillian (Jill Esmond) asks Cardigan to take her places like a hanging. He takes her to a boxing match and a speakeasy. She wants to marry a governor, and so they get married. Cardigan goes to tell June; she wants to quit, but he says he loves her. Cardigan goes out getting drunk alone. He turns Lillian away from his bachelor quarters and gets the marriage annulled.
June sees Powers shoot Bird Legs Duffy on the street. He warns her not to tell Cardigan. Cardigan arrests Powers. June was arrested as a witness but denies seeing it; so Cardigan releases her. June is called as a witness by the defense, but Cardigan brings out the truth in his cross-examination. To the jury Cardigan admits he worked for Powers and that he has a criminal record, giving up his chance for the governorship. He announces he is retiring from prosecution to return to defense, which makes June very happy.
Cardigan uses clever tricks to win his cases but ultimately he agrees with June that it is better not to be on the side of the police. Although probably a former prostitute, she is eager to help him cure his alcoholism. Ultimately Cardigan gives up ambition for love.