The film begins with French, English and German school boys reciting xenophobic, jingoistic war poems:
Child, upon these maps do heed this black stain to be effaced
Omitting it, you would proceed yet better it in red to trace
Later, whatever may come to pass promise there to go you must to fetch the children of Alsace
Reaching out their arms to us
May in our fondest France Hope's green saplings to branch
And in you, dear child, flower
Grow, grow, France awaits its hour.
To rid the map of every trace
Of Germany and of the Hun
We must exterminate that race
We must not leave a single one
Heed not their children's cries
Best slay all now, the women, too
Or else someday again they'll rise
Which, if they're dead, they cannot do.
We have one and only enemy
Who digs the grave of Germany
Its heart replete with hatred, gall and envy
We have one and only enemy
The villain raises its murderous hand
Its name, you know, is England.
Hearing such words from the mouths of children is of course horrible, explicitly showing us how the war developed on ethnic and national rivalries or hatred. The film proceeds, introducing us to its British, French and German characters who join up as the war breaks out. William and Jonathan, two Scottish brothers, along with their priest, Father Palmer, who joins as a chaplain, French Lieutenant Audebert (Guillaume Canet) and German tenor Nikolaus Sprink who is engaged to a Danish soprano, Anna Sørensen (Diane Kruger), reluctant to see him go. The characters are sent to the Western Front and face each other in the trenches.
On Christmas Eve, all sides decide to call a truce. Father Palmer presides over a service, Nikolaus and Anna sing carols, a football match is played, and soldiers from all sides share food and photos of their loved ones. However, when news of the fraternization across lines begins to leak out, the commanders worry that it could hamper the war effort, and take extreme measures to put a stop to the fragile peace.
- Badass Preacher: While he was as a stretcher bearer and not a soldier, Father Palmer was undeniably Badass. He went into no man's land twice to save someone's life without a thought.
- Bittersweet Ending: Every unit is reprimanded for their fraternization and are all split up to fight in new areas, but the Germans singing in the train at the end proves that they will never forget the humanity they showed their enemies.
- Brave Scot: Well, naturally. Special mention to Father Palmer, who doesn't quite fit the stereotype (being a non-combatant), but is nonetheless incredibly courageous in his efforts to save wounded soldiers and bringing a few days' peace to the battlefield.
- Cheese Eating Surrender Monkey: Utterly averted. Of all factions, the (on-site) French soldiers are repeatedly shown to be the most reluctant to parley with the enemy (which is understandable, since they're waging a defensive war literally on their home turf).
- Christianity is Catholic: Considering that Presbyterianism is the predominant Christian denomination in Scotland, it's a little odd that all the clergy who appear in the film are Roman Catholics. However, they are from the Highlands, an area which is mostly Catholic (the only region of Scotland where Catholics are the majority, actually).
- Cute Kitten: The Germans and the French use a cat to send messages back and forth across the lines. Which perhaps ends badly for all involved. General Audebert, the French lieutenant's father, tells his son at the end of the movie that the cat has been found guilty of espionage and sentenced to death, with a very serious face (this was based on a real incident, and the cat was shot).
- Decoy Protagonist: The film opens with Jonathan and William getting ready to go to war, with Father Palmer following reluctantly. It seems like the brothers will be our main characters, but the next time we see them, William is dying from a bullet wound and Jonathan fades into the background. If there is one protagonist in the Ensemble Cast, it's Sprink, who is met next.
- Deliberate Values Dissonance: Lots of the expected political incorrectness all around. Most of it comes off as harmless banter, except of course for the Kronprinz's antisemitism...
- Dressing as the Enemy: Played with with Private Ponchel, Lieutenant Audebert's orderly, to whom a German soldier lends his uniform so he can go through the lines and see his mother. It ends badly.
- Everything's Louder with Bagpipes: Subverted. While several of the Scots soldiers play the bagpipes, it's quite haunting and lovely.
- A Father to His Men: All three lieutenants, to some extent, but Audebert is the most obvious example. He is determined to stay alongside his men even during the most suicidal offensives, he is always polite to his subordinates, and twice he cradles a fallen soldier.
- Foregone Conclusion: None of the characters are very likely to survive the carnage of the next four years, but in particular, Horstmayer is Jewish. And in what appears to be a thinly-veiled allusion to his eventual fate should he survive the war, the last scene of the film shows the Kronprinz, a future Nazi sympathiser, apparently making an anti-Semitic comment before sending Horstmayer and his men to Eastern Europe in cattle cars.
- Foreshadowing: Jonathan's frequent Traitor Shots and Sanity Slippage shots make it all the more logical that he's the one who guns down the French Lieutenant's orderly.
- Friendly Enemy / Go-Karting with Bowser: The whole point of the film, which depicts fraternisations on the Western Front on 1914 Christmas Eve and Christmas Day.
- From the Mouths of Babes: Invoked in the opening scenes mentioned above, when French, British and German children are made to recite propaganda poems. On the Sliding Scale of Idealism Versus Cynicism, the French poem sounds idealistic enough, but the British and German poems are extremely cynical.
- Germanic Depressives: Lieutenant Horstmayer is a strict and by-the-book figure, who sees the Kaiser's Christmas trees and Anna's presence as frivolous annoyances.
- Good Versus Good: With two sides of people fighting for their countries in the name of justice and yet still show the kindness to their enemy so they can make peace for Christmas day. They then hate when they have to continue fighting their enemy even after they made friendships with others.
- Got Volunteered: Sprink mentions this specifically, but most of the other soldiers qualify as well.
- Heel Realization: The French Lieutenant when he tells his father "I feel closer to these 'monsters' than any man who says ''death to krauts!" over a stuffed turkey."
- Heroic BSoD: Jonathan undergoes one when his brother dies.
- Holiday Ceasefire: Based off the Real Life Christmas Truce of 1914.
- Humans Are Good: It portrays the humanity and kindness of all the soldiers on both sides who agreed to a truce.
- Insignia Rip-Off Ritual: Subverted. The Kronprinz just pokes his cane at it.
- Ironic Juxtaposition: Dramatic example. After the mass, with Christmas spirits running high, Nikolaus and Anna settle down to sleep, embracing happily beneath a blanket in the trenches. Cut to Jonathan lying in the snow, holding his dead brother.
- Kick the Dog:
- Or, crush the harmonica under the boot, by the Kronprinz as he dresses down the German soldiers who are being reassigned to the Eastern Front.
- The French general, who is also the French lieutenant's father, reveals that the cat was caught with a message from the Germans and has been found guilty of treason.
- Lost in Translation: Inverted. In the original multilingual cut, the Crown Prince's comment to Horstmayer didn't actually hint at any antisemitism - he was only commenting on the fact that Iron Crosses were now awarded "to just about anyone now" (or, in Horstmayer's case, 'cowards').
- Man in a Kilt: Quite a few of the Royal Scots Fusiliers.
- Mistaken Nationality:
- When Nikolaus goes "over the top" singing Adeste Fideles, he finishes by calling out, "Guten Abend Engländer!", to which an amused Scot replies, "Good evening, Germans. But we're not English, we're Scottish!"
- The châtelains assume that Danish Anna is German. She does initially address them in German, before switching to French (and the actress is German).
- Pet the Dog: One of the figures of high command (Audebert's father), ends up accepting that he and his son's view differ on the matter and, when learning that he has a grandson now, says "Let's both try to survive the war for his sake."
- "The Reason You Suck" Speech: One of these is given to each of the commanders of each army. Not a single one of 'em does anything but show how foolish and out of touch the high command is, and how messed up the war, and by extension all war, is.
- Reassigned to Antarctica: When word gets out, the French, German and Scottish soldiers are split up and sent elsewhere.
- Reality Is Unrealistic: Many said the sermon by the Scots Catholic bishop was "unreal" and "over the top." In fact it was taken from a real sermon, though by an Anglican bishop in Westminster Abbey. That actually makes it worse, as far more heard it. Here is the sermon, read it and weep:Bishop: "Christ our Lord said, 'Think not that I come to bring peace on earth. I come not to bring peace, but a sword.' The Gospel according to St. Matthew. Well, my brethren, the sword of the Lord is in your hands. You are the very defenders of civilization itself. The forces of good against the forces of evil. For this war is indeed a crusade! A holy war to save the freedom of the world. In truth I tell you: the Germans do not act like us, neither do they think like us, for they are not, like us, children of God. Are those who shell cities populated only by civilians the children of God? Are those who advanced armed hiding behind women and children the children of God? With God's help, you must kill the Germans, good or bad, young or old. Kill every one of them so that it won't have to be done again. The Lord be with you."
All: "And also with you."
Bishop: "May God Almighty bless you. The Father, the Son, the Holy Ghost. Amen."
- Screw Destiny: More of a "screw the church," but Father Palmer definitely has this after he overhears the above sermon, leaving his cross on a stand as he walks out the door. This is also a good example of....
- Screw the Rules, I'm Doing What's Right!: When the Bishop dresses Father Palmer down, Palmer responds, quietly but firmly, that he considers the Christmas Eve Mass he led to be the most important one of his life, and he'll never regret it. He further challenges the Bishop, asking if the Bishop actually believes he is doing God's work. The Bishop deflects the question, questions Palmer's role in the Church, and orders Palmer to go back to Scotland. After hearing the Bishop's sermon, Palmer quits the Church, and it's strongly implied that he will go right on working as a stretcher bearer and acting as an unofficial priest for the soldiers.
- The Smurfette Principle: Anna is the only woman in the film. Justified by the setting.
- Switch to English: Whenever the three lieutenants speak with each other. Justified as English is the only language the three men have in common. When the French and German lieutenants meet, the language of choice is French, which the German speaks fluently, being married to a Frenchwoman and all.
- Universal Chaplain: The film has a Christian priest (who is serving as a stetcher-bearer in the British Army) holding a Christmas Eve religious service. After some hesitation, a Jewish German officer joins in.
- Vomit Discretion Shot: Audebert gets one in his first scene, when he vomits out of fear before leading his men over the top towards a torrent of German machine-gun fire.