Sergeant Bill Thatcher, the head of an American battalion fighting for control of a French village. He is assigned to slow down the advancing Germans while American forces withdraw.
As Thatcher listens, three wounded soldiers under his command recall how they came to the battlefields of World War I: A farm boy, Bud, defied his mother and enlisted despite being the family's sole breadwinner; a New York playboy, trapped between two women, Ina, his newest conquest, and a former mistress, Lew , sought the easy way out by enlisting; finally, Private Jim Mobley tells the heartfelt story of how his wife, "Mademoiselle" Fritzi , a carnival knife thrower, got very upset when he decided to escape housekeeping duties (and being her target) by joining the army.
Back on the battlefield, Jim finds Bill at the machine gun, where the latter finally tells his own story of how he came to hate his German-born fiancée, Katherine, when she warned him of the futility of war. Before blowing up a railroad bridge, Bill admits to Jim that he now fully understands Katherine's sentiments. Wounded in the battle, both soldiers end up in a German Red Cross hospital where Bill is reunited with Katherine.