Warfare
This film exposes the atrocities of war. The generals give orders to more lowly soldiers to complete dangerous missions, and the young soldiers must face countless near-death experiences in their quest for success and heroism. Around every turn in Schofield and Blake's journey is a new danger that threatens both of their lives and threatens to undermine the entire operation.
The film also examines the terrible conditions in the trenches, the bad weather and the treatment of the soldiers. Many of the soldiers are depicted as being depressed and traumatized due to their experience, without access to good food, adequate rest, or sanitary conditions. Mendes' film shows both the glory and the horrors of the First World War, the sacrifices that the soldiers made, and the selflessness they exhibited in the process.
Loss
The threat of death and loss is always in the background in 1917. When Schofield and Blake initially set out, they are worried about the danger that lies ahead, but also motivated by the fact that if their mission is successful, they can prevent the loss of innocent lives. Not long into the mission, Blake is killed by a German pilot. Blake's death scene is particularly upsetting to watch. On his death bed, he asks Schofield, "Will you write to my mum for me? Tell her I wasn't scared." Blake's death is difficult for Schofield to come to terms with, but he uses it as motivation to find Blake's brother and save his battalion. While the film is an action movie, the central theme in it is loss, and the characters are haunted by the senseless deaths of their fellow soldiers.
Bravery
The bravery of both Schofield and Blake is a key theme in the film. Blake saves Schofield's life when a trench collapses on him, and then tries to save a German pilot whose plane had caught on fire. Unfortunately, the German pilot does not return the kindness, and he fatally stabs Blake. Following this, Schofield dusts himself down and continues his journey, displaying extreme bravery throughout. The film examines the ways that human beings carry on and try and do what is best for others, even in the face of extreme adversity. In the context of the film, bravery is not necessarily explicitly rewarded by the authorities, but is important nonetheless. Schofield is an exceedingly brave young man, doing whatever it takes to deliver the message he was tasked with delivering. Bravery in the film is a discreet virtue, a way of doing the right thing no matter the cost.
Fear
Early in the journey, Schofield is very fearful about the mission that they must go on. He expresses his regret at having gone on it, wants to wait until nightfall to embark, and exhibits very little enthusiasm. Especially after his near-death experience, Schofield is frightened of all of the unknown dangers to come. However, after Blake dies, his fear is replaced with determination and devotion to the memory of his friend. While he remains frightened and trepidatious at other moments in the film, he keeps it under control in order to succeed in his mission and honor the memory of his friend.
Solitude
A more implicit theme in the film is solitude. In one sense, war is lonely because soldiers are separated from their friends and loved ones and prevented from enjoying their camaraderie by the threat of death. Additionally, the theme of solitude and loneliness comes up explicitly when Blake dies early in the journey. From then on, Schofield must continue on his journey alone, with no one with whom to strategize or conspire. He is a lonely man, wandering no man's land without an accomplice. Mendes subtly examines the alienating effects of war, as well as the alienating effects of being called upon to complete heroic acts.
Peacefulness
The film has a very specific structure, flowing between moments of peacefulness and quiet and moments of great cacophony and danger. The first image of the film is of Schofield and Blake sleeping under a tree, before they are informed about their mission to deliver the message to the Second Battalion. After the explosion in the barracks in no man's land, and Schofield's near brush with death, Blake and Schofield have a brief moment of peace and Blake tells a funny story. Soon new dangers emerge when the German plane crashes nearby and Blake is stabbed.
A pattern emerges in which the narrative alternates between moments of action and drama and moments of repose. Schofield has a moment of melancholy peacefulness when he climbs on the truck carrying other English soldiers. He then finds some peace while hiding in the bombed-out building with the French woman and the baby she is caring for. He then experiences peace when he stumbles upon the Second Devons in the forest, and listens to one of the soldiers singing an English ballad. Finally, at the very end, we see Schofield returned to a seat under a tree, knowing his mission has been accomplished. The film examines the small, quiet, interior moments that exist amidst the violence of war.
Repression
After Blake dies, Schofield does not get much time to mourn. A group of soldiers finds him and invites him to join them, with the general pulling Schofield away prematurely from Blake's body. Smith then gives Schofield some private advice: "I’m sorry about your friend. May I tell you something that you probably already know? It doesn’t do to dwell on it." In this line the general reveals his belief that repressing one's feelings is necessary in order to do one's job. In the eyes of the soldiers, repression is a key tool to adopt in order to harness one's bravery. Only at the end, when the task is completed, can Schofield fully experience his grief at having lost his friend.
