On the front in Italy during World War II, a sergeant thinks that one of his men is faking battle fatigue, and sets out to expose him.

Johnny Wade, a recently decorated American soldier serving in Italy in 1943, suffers from shell shock. His sergeant, Rance, jealous of Wade's medal, thinks he is faking, but Gil Evans, an old friend of Johnny's from his youth in an orphanage, persuades an officer to send Johnny for medical treatment. Rance, planning to kill Johnny, encourages him to escape and then volunteers to capture him. Evans and Sergeant Wrigley are detailed to go with Rance, and after they leave their base is destroyed by a German attack. The three men, heading for the American lines, encounter Johnny and rescue him from the Germans. But after Rance mistreats him, Johnny runs away and takes refuge with Maria, an Italian.