Karl "Curly" Casterline, a wrongfully discharged New York City policeman, finds work on the Midwestern farm of Adolf Bauerle to help the war effort. Curly is attracted to his boss's niece, Mina, but also realizes that Adolf and his cohort, Kurz, plan to blow up a troop train. Curly kills the two saboteurs and saves the train, but he is jailed by the abusive Sheriff Herman Lindig. Although Mina praises Curly for saving the soldiers' lives, he is sentenced to death and is denied a pardon from the governor. After the case attracts national attention, the governor explains that he prolonged Curly's incarceration to draw attention to the danger of German propaganda.

Young lawyer Peter Donaldson tries to achieve fame by defending a man accused of murder, but the case is complicated by his love for a woman who is a witness for the prosecution.