Scrappy Irish-American Private Jerry Plunkett (James Cagney) is brash and defiant as his regiment trains for war, provoking his superiors and playing the rebel. On the battlefield, however, he proves cowardly, placing the lives of his fellow soldiers at risk. Only Father Duffy (Pat O'Brien) is willing to give Plunkett another chance. As the stakes grow higher and the battlefields lay covered with the dead, his moment of truth may prove either heroic or disastrous.