During the tumultuous period of World War II, Wehrmacht Colonel Claus Von Stauffenberg, portrayed by Tom Cruise, finds himself gravely injured during an RAF air raid in Tunisia, resulting in the loss of a hand and an eye. After being evacuated back home to Nazi Germany, things begin to escalate as Major General Henning Von Tresckow (played by Branagh) devises a desperate plan to eliminate Adolf Hitler. He attempts to smuggle a bomb onto the Führer's personal aircraft, but unfortunately, the bomb fails to detonate, leading Tresckow to Berlin to recover it safely. In the face of mounting challenges, he orders General Olbricht (portrayed by Bill Nighy) to find a substitute after the Gestapo arrests Major General Hans Oster.
Stauffenberg is then drawn into the German Resistance, where Olbricht introduces him to a clandestine committee that has attempted to assassinate Hitler in the past. Among the participants are General Ludwig Beck, Dr. Carl Goerdeler, and Erwin Von Witzleben. To Stauffenberg's shock, he learns that there are no contingency plans for what follows should Hitler be eliminated.
Amidst an air raid over Berlin, an inspiration strikes him — utilize Operation Valkyrie, a protocol designed to mobilize the Reserve Army to ensure order during a national emergency. The conspirators cleverly adjust the operation's orders to enable them to dismantle the Nazi regime after the assassination of Hitler. Recognizing that General Friedrich Fromm, the leader of the Reserve Army, holds the key to initiate this operation, they extend an invitation for him to lead the Wehrmacht in a post-Nazi Germany. However, Fromm is reluctant to directly partake in the plot.
To solidify their plans, they realize that the rewritten Operation Valkyrie documents must be signed by Hitler himself. Stauffenberg visits the Führer at his Berghof estate, where he is surrounded by prominent figures such as Dr. Joseph Goebbels, Wilhelm Keitel, Heinrich Himmler, Hermann Göring, and Albert Speer. During this meeting, Hitler praises Stauffenberg for his bravery in North Africa and unwittingly signs the modified orders, naively believing they are "for the best."
At the insistence of Goerdeler, Stauffenberg receives orders to assassinate both Hitler and Himmler at the Wolf's Lair, Hitler's command bunker. In a meeting prior to the plot, Colonel Mertz Von Quirnheim provides instructions regarding the bomb detonation. Stauffenberg also secures the cooperation of General Fellgiebel, who oversees all communications at the Lair, to cut off communication lines post-explosion.
On July 15, 1944, Stauffenberg attends a strategic assembly at the Wolf's Lair, carrying a briefcase bomb. However, he soon learns that Himmler is not present, which delays his opportunity to proceed with the assassination. As the meeting concludes, he faces bureaucratic hesitation from the committee; the turmoil within his ranks becomes evident as Olbricht mobilizes the Reserve Army without Fromm's knowledge, under the pretense of training exercises.
Despite securing his own escape and the safety of the bomb, Stauffenberg is confronted by Fromm, who warns him against taking further control over the army, threatening arrest. Stauffenberg, exasperated by the committee's procrastination, vehemently criticizes Goerdeler, who is slated for chancellorship after the coup.
On July 20, 1944, Stauffenberg returns to the Wolf's Lair with Lieutenant Haeften. To his dismay, he realizes that the meeting is being conducted in a summer barrack with open windows, leaving the bomb's potential destructiveness compromised. He meticulously positions the briefcase close to Hitler before stepping outside to wait for the explosion. However, an officer inadvertently shifts the briefcase behind a table leg, drastically reducing the blast's damage. Convinced that Hitler has been killed, Stauffenberg anxiously flees the scene.
As Stauffenberg heads back to Berlin, chaos ensues as reports surface that Hitler might have survived. Olbricht hesitates to mobilize the Reserve Army, fearing repercussions should Hitler still be alive. Unbeknownst to him, Mertz forges his orders to proceed. With Operation Valkyrie initiated, Stauffenberg and his allies command the arrest of key Nazi figures, but confusion abounds as lower-ranking officers become uncertain of their allegiance in the midst of rising suspicions regarding Hitler's fate. The General's refusal to join the plotters culminates in his detention.
As confusion deepens, Major Otto Ernst Remer mistakenly confirms Hitler's survival during a captivating phone call with Goebbels, leading to their recognition that they have contributed to a coup rather than quelling it. The plotters quickly find themselves besieged in the Bendlerblock as the headquarters escapes and the resistance leaders are captured. In a desperate attempt for self-preservation, General Fromm hastily organizes a court martial against the conspirators, defying Hitler's explicit orders for them to remain alive. Ultimately, the ringleaders meet grim fates: Colonel Stauffenberg's final words echo through history as he cries out, "Long live sacred Germany!" before facing a firing squad.
The concluding moments reveal that the conspiracy of July 20, 1944, marked the final of fifteen documented assassination attempts on Hitler orchestrated by Germans. Interestingly, the narrative also mentions Hitler's demise nine months later and the survival of Countess Nina Von Stauffenberg and her children through those dark times. A poignant dedication at the Memorial to the German Resistance serves as a reminder: You did not bear the shame. You resisted. You bestowed an eternally vigilant symbol of change by sacrificing your impassioned lives for freedom, justice, and honor.
