During the Western Desert Campaign of World War II, two Allied officers in Egypt are chosen to lead a dangerous commando mission behind German lines in Benghazi. Major David Brand, Curd Jürgens, a South African regular army officer, is capable and disciplined but lacks command and combat experience, and he does not speak Arabic. He has only a limited knowledge of Libya. Captain Jimmy Leith, Richard Burton, a Welsh amateur volunteer, brings extensive knowledge of the terrain and fluent Arabic, making him an essential partner in the risky operation. It is decided that both officers will go, with Brand in command. The men quickly form a tense dynamic, and Brand is seen by the unit as a strict disciplinarian —
> "the only thing he's slept with is the rule book."
Brand's wife, Jane Ruth Roman, is a Women’s Auxiliary Air Force Flight Officer who enlisted to stay near her husband. When Brand invites Leith to drinks with his wife, he learns that the two had an affair before she married Brand. Leith had walked out on her without explanation, a revelation that will haunt the mission.
The team parachutes into Benghazi with orders to attack a German headquarters and retrieve secret plans stored in a safe, which must be opened by Wilkins — Nigel Green — an experienced safecracker. They pose as local civilians to blend in, and the mission proceeds with nerves on edge. Brand’s hand shakes with fear when he must knife a German sentry, a deed that is ultimately carried out by Leith.
The operation is completed with minimal bloodshed: one man killed and one wounded on the British side. The patrol ambushes a German detachment and captures Oberst Lutze — Fred Matter — who Brand knows is responsible for the secret documents. In an apparent effort to get Leith out of the way, Brand leaves him alone with two gravely injured men, one British and one German.
Leith makes a compassionate, controversial choice. A German soldier pleads for life, and the Briton urges Leith to act quickly, but the firearm is empty and cannot be reloaded. Refusing to abandon the man, Leith lifts him and attempts to carry him to safety, while the German prisoner curses Leith’s failure. Leith’s Arab friend has joined him, and together they catch up with the rest of the unit.
The escape plan falters when the group discovers the others left behind have been murdered and the camels seized. On the long trek back across the desert, Brand’s resentment toward Leith grows, driven not only by the affair but by the fear that Leith will reveal Brand as a coward to headquarters and ruin his career. During a rest, Brand notices a scorpion climbing Leith’s leg but does not warn him in time. When Leith is stung, Brand refrains from shooting him as his orders permit and allows him to die in the pain of the sandstorm. Rumors swirl among the men that Brand killed Leith, though the truth remains unsettled.
Ultimately, a patrol rescues the group and returns them to headquarters. Back home, Jane is distraught to learn of Leith’s death, and Brand is immediately awarded the Distinguished Service Order. Rather than celebrate, she walks away in sorrow. In the closing image, Brand ruefully pins the medal on a stuffed training dummy, a stark reminder of the price paid in a mission governed by duty, pride, and a brittle sense of honor.
