Shot in a compelling docudrama style, this film delves into the harrowing days leading up to D-Day, showcasing pivotal events across both the Allied and Axis fronts during this historic military endeavor. As the Allies anxiously await a respite from the relentless poor weather conditions, they also brace for the reaction of the German forces tasked with defending northern France.

At the forefront of the Allied forces is Lieutenant Col. Benjamin H. Vandervoort, portrayed by John Wayne, who commands a determined parachute infantry division. As tensions rise, Benjamin relays crucial intelligence to Brigadier Gen. James M. Gavin, played by Robert Ryan, the commanding officer of the airborne division. His mission is monumental: seize Sainte-Mere-Eglise, a strategic point lying along the sole route that could be exploited by the Germans to target the allies’ northern flank. With only a mere four-mile descent to navigate before reaching the town, Vandervoort must confront the fierce natural obstacles posed by swamps that the Germans have deliberately flooded. Demonstrating quick thinking and innovation, Benjamin supplies his men with clicking toys to ensure they can identify one another amidst the chaos of darkness.

Meanwhile, Brigadier Gen. Norman Cota, played by Robert Mitchum, serves as the assistant commander of the 29th Infantry Division. He grapples with growing unease as assault forces remain cooped up aboard their ships for an extended three-day period, waiting for a much-needed break in the weather. It becomes increasingly evident that the decision of whether to proceed with the invasion lies squarely on the shoulders of General Dwight Eisenhower, depicted here as a steadfast leader in a pressure cooker situation.

Flying Officer David Campbell, portrayed by Richard Burton, represents the relentless spirit of the RAF as he also plays a vital role amid the unfolding crisis. Alongside him is Group Capt. J. M. Stagg, a dedicated meteorologist whose assessments are critical in determining the fateful go-no-go decision.

Within the ranks of the German command, Generalfeldmarschall Gerd Von Rundstedt, as portrayed by Paul Hartmann, contemplates potential threats while Major Werner Pluskat, played by Hans Christian Blech, oversees the coastal defenses. Concurrently, military intelligence officer Oberstleutnant Helmuth Meyer grows increasingly convinced that an imminent attack is on the horizon. However, his superiors remain hesitant, fearing that the poor weather will thwart any invasion attempts.

As dawn approaches on June 6th, multiple storylines unfold, commencing with the crucial airborne missions that signal the onset of D-Day. British troops, in a daring glider operation, aim to secure Pegasus Bridge, while Major John Howard, played by Richard Todd, is entrusted with a daunting task—maintaining control of the bridge to prevent German demolition, which would cut off the Allies’ pathway into Normandy.

Chaos ensues as American paratroopers drop into Sainte-Mere-Eglise, many dispersed and subjected to harrowing conditions—half of them landing in swampy hell while the others face fierce resistance within the town itself. The valor exhibited by the French Resistance, featuring characters such as Father Louis Roulland, played by Jean-Louis Barrault, showcases their dedication to sabotaging enemy operations, as they work tirelessly to disrupt communication and troop movements.

The early hours underscore the uncertainty and miscommunication rippling through the German hierarchy as they grapple with the question of whether this could be a mere feint or indeed the actual Allied invasion. With Hitler sluggishly asleep, significant decisions remain unmade, ultimately proving catastrophic in the decision-making chain.

The stark reality is poignantly captured as the Allied forces mobilize—through the sweat and blood of their soldiers, they manage to breach defensive lines, culminating in Benjamin’s relentless push through Sainte-Mere-Eglise after fierce engagements. The psychological weight is palpable as they confront the aftermath of heavy losses amongst their ranks.

In a brilliant montage that encapsulates the united Allied effort during this tumultuous invasion, the film closes on a hopeful note, highlighting diverse units consolidating their positions along the beaches, ready to march forward into the heart of France on their journey towards liberation and the eventual confrontation with tyranny.