In July of 1944, a month after D-Day, a small squad of American soldiers make their way through the deadly battlefields of Normandy, part of the attempt by the Allied forces to re-claim France. Led by Sergeant Walker, the men are weary, and anything but unified. Cynical Private Joe Faraday takes bets on how many casualties there will be at the end of each day. Private Eddie Rourke, full of optimism, is constantly at odds with Joe. Privates Nick Dante and Homer Stucky comprise the rest of the squad. Monica, on a Search and Rescue mission, watches over the men unseen.

Through a flashback, we learn that the feud between Eddie and Joe began several months earlier, in an Allied canteen. Joe is upset to find Eddie dancing with Stella, a USO hostess whom Joe considers his girl. Stella isn’t interested in Joe and tries to let him down easy. Tess, a USO singer, tells Monica that she is assigned to Joe, that she must help him decide to become a hero. Back on the battlefield as the combat quiets down, the squad discovers Monica comforting a dying German soldier and they take her prisoner. Just then, Sergeant Walker is shot and dies. The squad holds Monica partially responsible, and Joe wants to execute her, but cooler heads prevail. Homer, in a panic, tries to radio HQ, but accidentally uses a German radio revealing their position.

Knowing that they are now sitting ducks, Monica encourages the men to write letters to their loved ones, and to make a pact that whoever survives will deliver them. All agree except for Joe, who recalls the night in the canteen when, rejected by Stella, he tries to hit Eddie, but Eddie knocks him down first. At this moment the air raid sirens sound, signaling for everyone to take cover. As the crowds gather in the London underground , Joe meets a small boy named Rupert, with a birdcage, who is lost. Joe is shaken out of this memory by the news that a German tank is approaching. Monica prays, but Homer and Nick fall, and Eddie is wounded. Monica and Joe help Eddie to a farmhouse where he realizes that they left the letters behind. He pleads with Joe to find them, but Joe refuses. Eddie tells Joe that he and Stella were married the night before they shipped out, but Joe tells Eddie that Stella married him too, so that she could cash his paycheck. Monica slaps Joe for the lie and reveals herself to Eddie, telling him the truth before he dies. Later, Monica reveals herself to Joe, telling him that God loves him, but that his moral compass is broken. She tells him about the greatest love — laying down your life for your friends.

Joe goes to find the letters and, instead, finds Andrew digging graves for the dead soldiers, and Andrew gives him the letters. When he brings them back to Monica, she promises to deliver them. Joe admits that he feels like he’s finally done something important. As he rejoices, he is shot by a German soldier. As he dies, Monica helps him compose a letter to Rupert. Joe writes that he fought this war for him, and for the generations to follow. Fifty years later, Monica enters a small London pet shop and comments on its beautiful birdcage. The old proprietor, Rupert, tells her the story of the birdcage, and shows her a framed letter from a soldier, the letter from Joe.