The crew of an M3 Lee tank, attached to the British Eighth Army, commanded by U.S. Army Master Sergeant Joe Gunn (Humphrey Bogart), and nicknamed Lulu Belle, become separated from their unit during a general retreat from German forces after the fall of Tobruk. Heading south across the Libyan desert to rejoin their command, they come across a bombed-out field hospital, where they pick up a motley collection of stragglers, among them British doctor Captain Halliday (Richard Nugent), four Commonwealth soldiers, and Free French Corporal Leroux (Louis Mercier). Halliday, the only officer, cedes command to Gunn.
Titled after a lyric in the Marines' Hymn, which contains the phrase "... to the shores of Tripoli" (which is, itself, a reference to the Battle of Derne) the film is one of the last of the pre-Pearl Harbor service films. When the film was in post-production the Pearl Harbor attack occurred having the studio shoot a new ending where Payne re-enlists.
In September 1942, Rommel's Africa Korps is only 90 miles (144 km) from the Suez Canal, but running dangerously low on fuel. The British approve a plan to destroy German fuel bunkers at Tobruk in an attempt to cripple Rommel's attack.
In 1929, Italian dictator Benito Mussolini (Rod Steiger) is still faced with the 20-year-long war waged by patriots in the Italian colony of Libya to combat Italian colonization and the establishment of "The Fourth Shore"—the rebirth of a Roman Empire in Africa. Mussolini appoints General Rodolfo Graziani (Oliver Reed) as his sixth governor to Libya, confident that the eminently accredited soldier and fascist Grande can crush the rebellion and restore the dissipated glories of Imperial Rome. Omar Mukhtar (Anthony Quinn) leads the resistance to the fascists. A teacher by profession, guerrilla by obligation, Mukhtar had committed himself to a war that cannot be won in his own lifetime. Graziani controls Libya with the might of the Italian Army. Tanks and aircraft are used in the desert for the first time. The Italians also committed atrocities: killing of prisoners of war, destruction of crops, and imprisoning populations in concentration camps behind barbed wire.
Corporal John Bramble (Franchot Tone) is the sole survivor of a British tank crew after a major battle with Erwin Rommel's victorious Afrika Korps. Delirious, he stumbles across the North African desert into the Empress of Britain, a small, isolated hotel owned by Farid (Akim Tamiroff). The staff consists of just Frenchwoman Mouche (Anne Baxter), as the cook has fled and the waiter Davos was killed the night before by German bombing.
In mid-April 1941, during World War II, German Field Marshal Erwin Rommel (James Mason) and his Afrika Korps have driven the British Army into headlong retreat across North Africa toward Egypt and the vital Suez Canal. Standing in Rommel's way is Tobruk, a constant threat to his supply lines. The 9th Australian Division are asked to hold the port for two months, at which time they are to be relieved.
In North Africa, experienced Sergeant Kelly (Thomas Mitchell) leads out a British patrol, accompanied by Corporal Colin Spence (Henry Fonda), an unassertive Canadian. When they are attacked by Italian airplanes, they manage to shoot one down, but it crashes on one of their vehicles, killing eight men. Later, Kelly leads the six survivors on an attack of an Italian armored car, but is seriously wounded. He orders Spence to leave him behind; when Spence refuses to obey, he shoots himself.
In the days after the Dunkirk evacuation in Second World War, recently commissioned Second Lieutenant Jim Perry (David Niven), a pre-war Territorial private soldier and a veteran sergeant of the British Expeditionary Force, is posted to the (fictional) Duke of Glendon's Light Infantry, known as the 'dogs', to train replacements to fill its depleted ranks. A patient, mild-mannered officer, he does his strenuous best to turn the bunch of grumbling ex-civilians into soldiers, earning himself their intense dislike. The conscripts also believe that their sergeant is treating them with special severity; in fact, he is pleased with the way they are developing and has his eye on some of them as potential NCOs. Eventually however, the men come to respect their officer.
Au point culminant de son avance en Égypte en 1942, l'armée italienne approche d'El Alamein, où les Britanniques se défendent de pied ferme. Privées d'essence, les forces de l'Axe sont bientôt contraintes à la défensive. Le lieutenant italien Giorgio Borri, un patriote idéaliste qui croit encore en la victoire, est affecté à la division parachutiste Folgore (La Foudre). Son unité est envoyée dans le désert pour y tenir des tranchées et attendre l'inéluctable contre-offensive anglaise.
En 1942, en Afrique du Nord, une jeune femme (Marlène Jobert) aide un officier anglais (Michael York) à échapper aux Allemands, avec l'aide d'un escroc (Michel Piccoli) et d'un Tunisien (Amidou). Ils vivront mille aventures dans le désert.
In French Tunisia, during the Second World War, a convoy of the French Foreign Legion is charged to recover gold bars of six billion francs from a bank in El Ksour in order to bring them into a safe place for the French government.
Narrant la célèbre bataille d'El-Alamein, le film se place surtout du côté italien, car on voit les troupes italiennes encerclées et se battant avec bravoure et l'énergie du désespoir, même en sachant que tout était perdu, tandis que les troupes britanniques ne faisaient que « ramasser les miettes ».