William Faulkner wrote the story and dialog for this Howard Hawks film about heroic sacrifices and romance during war.
The American Richard Bogard (Gary Cooper) arrives in England in 1916 and rents the country home of Ann (Joan Crawford), who has just learned that her father was killed in the war. She tells Richard she is moving to the gardener's cottage. While they are on leave from the navy, Ann shows her brother Ronnie (Franchot Tone) and her fiancé Claude (Robert Young) her father's memorial. After spending some time together Richard tells Ann he is going to war because he loves her. She loves him too and volunteers as a nurse, finding Claude and Ronnie in France. Ann reads that Richard as a pilot has been killed. Claude tells Ann he is afraid, and together they tell Ronnie they didn't wait to get married.
Richard comes back to England and then finds Ann in France. As she starts to explain, Richard's partner McGinnis (Roscoe Karns) separates them. Claude is found drunk, and Richard helps carry him home, where he sees Ann. The next day Claude buys Richard a drink. Hearing what they do on the boat, Richard takes Claude in his plane to experience war, bombing a German ammunition works. Claude sees a bomb stuck but is ignored. When fighters attack them, Claude (without any training) shoots down three planes. Ann tells her brother Ronnie she loves Richard and wants him to understand. Ronnie invites Richard on their boat in the rain. While Germans shoot at them, they head for a ship and release a torpedo; but it gets stuck. Claude is shot in the face, and Richard releases the torpedo, blowing up the ship. Ronnie tells Ann that Claude's eyes are hurt, and the doctor says he is blind. Ann takes Claude home and then goes outside to talk with Richard. He realizes Claude loves her. Ann loves Richard and tells him Claude is blind; she kisses him, and he leaves. Claude tells Ann he likes Richard.
Richard and McGinnis volunteer to bomb a German cruiser. Claude tells Ronnie he knows that Richard loves Ann. Claude says they could get the cruiser first, and he sends a note to Richard to take care of Ann. Their torpedo gets jammed, and Ronnie tells Claude to jump off; but he refuses. Their boat crashes into the cruiser, sinking it, and Richard's plane turns back. In the final scene Richard and Ann look at the names of Ronnie and Claude on her family memorial.
Faulkner's original story shows the affect of war on the men fighting, but the movie version adds a woman and romance to the mix, revealing the folly of war that leads to such heroic sacrifices and loss.