In 1917, three law school graduates are on their way to register for the draft in World War I. En route to the recruiting office, they meet classmate J. Edgar Hoover, who invites them all to join him in the U.S. Department of Justice, thereby serving their country without facing death in the trenches. Two—Aloysius Gantt and Declan O'Hara—agree, while the third, Gregory Jordan, goes on to join the U.S. Marines.

On the home front, Gantt and O'Hara join in roundups of suspected draft dodgers and later, while Jordan is hospitalized for wounds suffered at Belleau Wood, they follow Hoover's lead into the Palmer raids, deporting alleged alien radicals to Russia.