During the tumultuous period of the First World War, young Second Lieutenant Raleigh, portrayed by Asa Butterfield, is dispatched to the front lines located in Northern France. With a heartfelt request to his uncle, General Raleigh, he seeks to serve under the command of Captain Stanhope, a man Sam Claflin who was a few years ahead of him at school and shared memorable holidays with both Raleigh and his sister, Margaret.
While Captain Stanhope is recognized as an exceptional leader, having earned the Military Cross for his bravery at the Battle of Vimy Ridge, he battles his own demons, relying on heavy drinking to cope with the grim realities of war. Surrounding Stanhope are other key officers, including the compassionate Lieutenant Osborne, played by Paul Bettany, affectionately referred to as ‘Uncle’ by his peers; the older, lower-class officer 2nd Lt. Trotter, represented by Stephen Graham; and 2nd Lt. Hibbert, whose desperate attempts to avoid the front line through feigned eye pain earn him the ire of Stanhope.
The officers of C Company form a close-knit team, uniting over three-course meals each evening, though these typically consist of whatever the mess cook can whip up from scarce supplies, starkly contrasting with the lavish dinners reserved for more senior officers. As Raleigh acclimates to his new role, he diligently carries out his duties, which include inspecting the trenches, overseeing the morning "stand to" for dawn defense, and learning the names of his men.
The looming threat of a German offensive weighs heavily on the battalion, especially after the commander informs Stanhope that intelligence from a deserter anticipates an assault on Thursday, 21 March 1918. To gather vital information for an upcoming visit from a brigadier, Stanhope is ordered to send two officers and ten men on a risky daylight raid into no man’s land with the objective of capturing German prisoners. The unfortunate selection of officers includes Lieutenant Osborne and Second Lieutenant Raleigh. Tragically, of the men sent, only four and Raleigh return, with one prisoner revealing the presence of a unit from Württemberg.
The aftermath of the raid leaves Stanhope heartbroken over Osborne's death. In his grief, he turns to alcohol, which ultimately leads to a volatile confrontation with Raleigh. As dawn breaks on 21 March, chaos ensues as shelling erupts, casting shadows of destruction. Amidst the turmoil, Raleigh suffers severe back injuries. Stanhope, in a moment of profound despair, lays him on a bed within the officers' dugout. Ignoring the urgent requests from the sergeant-major for him to regain command, he stays with the dying soldier, offering comfort as Raleigh, shivering from the cold, takes his last breath under a blanket.
Following this tragic moment, Stanhope exits in shock, surrounded by the deafening explosions that mark the battlefield. The following day reveals the harrowing scene of the Germans in gas masks, inspecting the captured trenches littered with the lifeless bodies of British soldiers. Back home, Margaret finally receives a letter from her brother, sent shortly after his arrival at the front lines, marking a poignant connection amidst the heartbreaking chaos of war.
