Belgium, December 16, 1944: First Lieutenant Thomas Hart, portrayed by Colin Farrell, finds himself captured by German commandos amidst the unfolding chaos of the Battle of the Bulge. After being taken to a local prison, his boots are confiscated, leaving him vulnerable and exposed in a cold cell. As the threat of frostbite and pneumonia looms, he is coerced into revealing intelligence to his German interrogator. Subsequently, he and a group of American soldiers are transported by train to a prisoner of war camp. In a dramatic turn of events, a squadron of P-51 Mustangs inadvertently attacks the train after the letters POW, obscured beneath layers of snow, are not visible. This tragic incident leads to the deaths of some POWs due to friendly fire, compelling the men to spell out POW with their bodies in a desperate attempt to avert further attacks.
Upon reaching the camp, Hart undergoes debriefing with the senior American officer, Colonel William McNamara, played by Bruce Willis. When questioned about his cooperation with the Germans, Hart denies any wrongdoing, though McNamara knows the truth, having observed Hart's three-day ordeal with a Level 1 interrogator. Instead of allowing him the comfort of bunking with fellow officers, McNamara assigns him to the barracks for enlisted men, a decision that deepens the tension between them.
Things become even more complicated with the arrival of two Tuskegee Airmen, Second Lieutenants Lincoln A. Scott and Lamar T. Archer, who are the only Black officers in the camp. Their position is made perilous by the hostility of Staff Sergeant Vic W. Bedford, a vile racist threatening their very existence. Soon, a spike found in Archer's bunk leads to a tragic escalation; the Germans seize Archer, executing him under the pretense of attempting to escape. Almost simultaneously, an American radio set up to receive coded messages is discovered and destroyed.
The stakes rise drastically when Bedford is later found dead, with Scott accused of his murder—a reprisal for being framed for Archer's execution. With his legal background as a former Yale law student, Hart is tasked by McNamara to defend Scott in a court-martial that gains the consent of the camp's commandant, Oberst Werner Visser.
As the trial unfolds, tensions flare. Visser hands Hart a manual on US Army court-martial procedures, thereby intensifying the clash with McNamara, who finds his authority questioned. On the stand, Scott delivers a poignant testimony about the grave inequities faced by Black soldiers who volunteered to serve their nation yet were met with scorn.
In a twist of fate during the trial, Hart uncovers a hidden tunnel, revealing an escape plan that McNamara discloses was intentionally crafted to distract from an impending attack on what the Allies erroneously believe to be a shoe factory. The truth soon emerges that Bedford had schemed to frame Archer and orchestrate an escape based on betrayal. Hart is horrified to learn of McNamara’s ruthless decisions, prioritizing the lives of many over the life of an individual to further their cause.
As the trial reaches its conclusion, McNamara and 34 men feign illness to evade participation, slipping away to execute their escape. In a moment of sacrifice during his closing argument, Hart asserts that he was responsible for Bedford's death in a bid to save Scott. This revelation leads to immediate repercussions, with Visser preparing to execute Hart for his claim.
However, in a remarkable turn of selflessness, McNamara returns to the camp, choosing to accept full responsibility for Hart's actions, even as an explosion adjacent to the camp signals the beginning of chaos. Moved by Hart's bravery, McNamara sacrifices his own life to spare the other prisoners.
In the aftermath, Scott leads the salute to McNamara's fallen figure. Three months later, as the German forces surrender to the Allies, the prison camp is liberated, marking an end to this harrowing chapter of their struggle.
