William Faulkner helped write this war story of a French company fighting in the trenches under two officers in love with the same nurse.
In 1916 France Captain Paul La Roche (Warner Baxter) is ordered back to the front and gives nurse Monique (June Lang) a cross on a necklace. She says it tears her heart. Lights are turned out for an air raid from a zeppelin. Monique takes cover with Lt. Michel Denet (Fredric March), who plays piano. He kisses her, but she won't tell him her hospital unit. Denet reports to La Roche, who says half his men are replacements. Sergeant Regnier (Victor Kilian) calls them La Roche's "hard bargains" and says he is the finest officer. La Roche sends back an old man as unfit. La Roche speaks of the regiment's record since Napoleon. The men march singing. At the front a wounded soldier caught in barbed wire moans; men died trying to get him. Two more volunteer, and Denet brings one wounded back. La Roche calls Denet a brave fool. Men in the dugout hear miners. La Roche tells them to go back to sleep, and Denet orders rum for them. Denet says he told the men he would get them out. Steel helmets are delivered. The company is relieved, and they see the mine explode under two platoons.
Monique calls on the sleeping La Roche. Denet finds her at the hospital; but she says she is busy for the duration. Later Denet gives her wine and plays piano for her. The allies plan their biggest push. Regnier tells men what to throw away but lets Moran (Lionel Barrymore) keep his trumpet secretly. La Roche gives Denet a packet to give to Monique in case he dies. Denet says he has nobody. La Roche gives the same speech about no man detracting from the record. He sees and summons Moran. Denet meets Moran, who is La Roche's father. La Roche sends Moran back as unfit. Denet finds Monique in his room, and she says how La Roche helped her family. Denet tells Monique not to tell La Roche that she loves Denet, not wanting to break them up. La Roche finds the necklace in Denet's room. Moran gets his transfer order; but he gives Sergeant Bouffiou (Gregory Ratoff) five francs, and they see that it is burned.
Denet tells La Roche that Moran fell on a bomb, a dud, and La Roche commends Moran. La Roche asks Denet for his packet. Amid artillery La Roche orders his men to advance. Germans retreat, and the French throw hand grenades. Moran says fear is only in the mind. In a church "Ave Maria" is sung, and Monique prays. At night La Roche's men are surrounded in a village. Denet volunteers to lead six men with Moran bringing a phone. Two men are shot, and Moran is afraid to go on. Denet connects the phone and calls La Roche, who orders them back. Moran throws a grenade, thinking they are Germans, and Regnier is killed. La Roche puts Moran under arrest.
Monique sees Denet having his arm bandaged. He kisses her, and they see La Roche; Denet says they love each other. La Roche is blind and puts Denet in command. Moran guides La Roche to the phone post, and they call in corrections to the artillery guns, dooming themselves. Moran blows his bugle, and they are killed. Monique and Denet read La Roche's letter. Monique asks Denet why he has to go and die. In the final scene Denet speaks to the replacements about the regiment.
This grim drama exposes the harsh reality of the world war, put in perspective by Bouffiou's letter saying he will be in a serious situation if he doesn't make his music-box payment. Officers say they are fighting for France and civilization, but how has France and civilization led them to this insanity?