Business tycoon James J. "J. J." MacGlennon is found guilty of corruption and sentenced to prison, along with his son Jonathan, who testified against him but feels he is also guilty because they are related. Jonathan, an intellectual socialist, disapproves of his father's business methods, which he believes indicate that J. J. has criminal proclivities. He and J. J. bicker all the way to prison, while J. J.'s business is taken over by his greedy vice-president, Percy Webb. Although Jonathan's cellmate is surly convicted killer Frank Lucacelli, Jonathan insists that they get along, and when Frank tries to strike him, Jonathan calmly knocks the killer out and continues his exhortation about man's need for humanity. As MacGlennon Enterprises' stock drops, and Webb forms a partnership with crooked lawyer Frederick Driscoll, J. J. instructs his still-employed secretary, Elinor Cantwell, to continue to buy stock on his behalf so that Webb will never gain control of the company. J. J. goes so far as to have Elinor purchase Webb and Driscoll's potassium mine because he thinks that their business sense is so poor that the mine must be valuable if they want to get rid of it. Reporter Whitey O'Neil comes to see Elinor to confirm rumors that Elinor is engaged to Jonathan, but Elinor vehemently denies the rumor because of her intense dislike of the self-absorbed intellectual. Jonathan receives a pardon after a board of inquiry determines that he was blameless for his father's machinations. Worried that his company will go under with Webb at the helm, J. J. seizes this opportunity to convince Jonathan that he has reformed, and now wants his son to run the company as he pleases. In truth, J. J. is counting on the probability that with Jonathan in charge, stock prices will plummet, and he will be able to buy up the dominating shares. Jonathan, however, is sincere in his desire to reform American business, and immediately confides in the cleaning woman, Yettie Kropatchek, a minor stockholder. An appalled Webb is ousted, while Jonathan starts instituting radical policies and interviewing small businessmen with whom he hopes to form an alliance. When every small business owner fails to be interested in Jonathan's plan, he becomes despondent and admits to Elinor that he has overestimated his fellow man. Jonathan then confesses his love for Elinor. Elinor is so moved by his compassion that she bursts into tears, and admits that she too loves him, but has been working on his father's behalf to ensure that all the businessmen would reject Jonathan's plan. Buoyed by this news, Jonathan kisses Elinor and finds renewed vigor to revolutionize business. Jonathan's model of business succeeds so well that it becomes an asset to the war effort, and the company is hailed nationwide. Webb, Driscoll and Webb's secretary Mimi, meanwhile, plot revenge against Jonathan, and hire an ex-convict to murder him. When the killer, Frank, recognizes his former cellmate, however, he refuses to kill him because he always treated Frank as an equal. J. J., who now wholeheartedly supports his son's business theories, obtains a special one-day release to attend the stockholders' meeting, and his appearance foils Webb's last attempt to take control. Whitey writes a story about J. J.'s change, along with the fact that Frank has accused Webb of attempted murder, and announces Jonathan and Elinor's engagement. J. J., who was released only because of Whitey's influence with the governor, then goes to see his son, who, at that moment, is being lectured by a Hungarian professor. The professor convinces Jonathan that his business theories will ultimately fail, and that capitalism and individual achievement are the only business methods that work.