In the spring of 1917, following the fierce Battle of Vimy Ridge, Sergeant Michael Dunne of the 10th Battalion, CEF, returns home from the war, having survived intense combat but suffering from neurasthenia—a psychological condition caused by the stresses of battle. Despite his physical and mental struggles, Dunne is celebrated as a hero for his bravery in taking out a German machine gun position. While receiving treatment in a hospital in Calgary, Alberta, where he initially enlisted, he forms a connection with Sarah Mann, played by [Caroline Dhavernas], a compassionate nurse tending to wounded soldiers.
Meanwhile, David Mann, [Joe Dinicol], Sarah's younger brother, is determined to enlist despite being deemed ineligible due to asthma. The Mann family faces social rejection when it becomes known that their father fought and died at Vimy Ridge for the Imperial German Army, a revelation that complicates the family's standing. However, David's resolve is strengthened by his girlfriend’s father, who intervenes to allow him to join the military. Wanting to protect David, Dunne, feeling a sense of responsibility for Sarah and her brother, reenlists under his mother’s maiden name, McCrae, pledging to keep David safe.
Dunne and David find themselves fighting side by side on the battlefields of Belgium, experiencing the brutal realities of war. Meanwhile, Sarah enlists as a nurse and accompanies the 10th Battalion to the frontlines, working in triage at an Advanced Dressing Station near the fighting zones. They arrive in Flanders just in time for the infamous Battle of Passchendaele, a grueling and muddy engagement. Dunne and Sarah cross paths once again when Dunne brings a wounded soldier to the aid station. His cover story as McCrae is soon uncovered, but he manages to evade punishment. Recognized for his leadership skills and combat experience—which mentioned actions "that should have earned him a V.C."—Dunne is promoted to platoon leader by Lieutenant Colonel Ormond, played by [Paul Gross], who knew him from earlier battles.
As the assault begins, the 8th Battalion (90th Winnipeg Rifles), known as the “Little Black Devils,” faces a fierce German counter-attack. The battalion is pinned down, exhausted and fighting desperately until Dunne's company is called in for support. After they arrive, the 8th Battalion begins to withdraw, believing they are relieved, leaving the difficult task of holding the line to Dunne’s small force. As the battle intensifies, the reality of war starts to sink into David’s consciousness, exposing him to its brutal and chaotic nature. During the night in the trenches, shelling causes a panic attack for David, which Dunne calms, demonstrating his growing concern and protective instincts.
The following morning, the Germans launch a counter-attack that pushes close to the Canadian line, leading to brutal close-quarters combat. In the chaos of retreat, David is overwhelmed and runs after the retreating Germans, attempting to surrender. He jumps into a German trench and pleads in German, only to be confronted with a gun. Just as he is about to be shot, an artillery shell lands nearby, causing a massive explosion that leaves David perilously trapped amidst debris resembling a makeshift cross—a visual echo of the legendary report of a crucified soldier that Dunne had told earlier. Seeing this, Dunne, played by [Gil Bellows], throws down his helmet and gun in a reckless act of heroism, running to save David. He is shot in the process but manages to crawl towards David, who is in a dire state. Amidst heavy fire, Dunne reaches out and, despite his wounds, runs to carry David back to their lines. The fighting resumes with renewed violence, and Dunne succumbs to his injuries in a hospital after sharing a last moment with Sarah. His final words are reflective of his sacrifice, and the news of the Canadian victory at Passchendaele Ridge arrives as he dies.
The closing scenes depict a poignant tribute: David, now a one-legged veteran in a wheelchair; Sarah Mann; David's girlfriend Cassie, played by [Meredith Bailey]; Highway, and Dunne’s close friend Royster (played by [Gil Bellows]) gather at Dunne's grave on his family farm. The gravestone has been altered to mark the year as 1917, removing the original "5" from 1915. As the camera pulls back, the scene transitions to a vast field filled with hundreds of Canadian war graves, with a riderless horse on the horizon, symbolizing the heavy toll of war and the enduring legacy of those who fought and fell.
