Following his graduation from law school, Senator Robert Maddox's adopted son Paul is offered a job at Bill Mellon's law firm. Mellon, an unscrupulous criminal lawyer, is actually Paul's real father, but keeps the fact a secret from him. When gambler Georgie Evans tells Mellon that he has just killed a man named Harrison in self-defense, Mellon advises him to turn himself in, and tells him exactly what say to keep him from going to prison. Mellon assigns Paul to handle Evans' case, and while Paul is on his way to police headquarters, Mellon, who lied about having killed Harrison, deliberately murders Harrison and makes it look as if he committed it in self-defense by following Mellon's prescribed advice on how to tell the story to the police. Though Mellon later discovers that he has been duped by Evans, he nevertheless agrees to let Paul defend him for a high price. Paul, unaware of his client's guilt, defends him in court and wins his acquittal. When Paul learns that he helped set a guilty man free, he resigns from Mellon's firm and gets a job as assistant district attorney. Soon after taking the position, Paul spearheads an investigation into legal malpractice, which worries Mellon and prompts him to assign Mitchell to implicate those investigating them in a scandal. Mitchell finds evidence that Mrs. Maddox is Paul's real mother, but when he refuses to hand it over to Mellon, Mellon and he fight over it and Mitchell is accidentally shot by his own gun. Paul successfully prosecutes his own father, who is convicted of second-degree murder because he refused to discuss the content of the papers over which he and Mitchell were struggling. After the sentencing, Mellon has Mrs. Maddox swear an oath of secrecy so that Paul will never know that his real father was sent to jail for a crime he did not commit.