Trama

The British military recruits a small group of highly skilled soldiers to strike against German forces behind enemy lines during World War II.

Billed as a true story about a secret British World War II organization; the Special Operations Executive. Founded by Winston Churchill, their irregular warfare against the Germans helped to change the course of the war, and gave birth to modern black operations.

Britain, at the height of World War II. To counter German advances in Europe, UK Prime Minister Winston Churchill indirectly launched the daring Operation Postmaster: an unsanctioned, unauthorised, and unofficial suicide mission. Orchestrated by Brigadier Colin Gubbins and Lieutenant Commander Ian Fleming, they assembled a team of dangerous Nazi-haters to get things done. As a result, the top-secret combat unit must use unconventional and ungentlemanly methods to destroy two German tug boats servicing the U-boats in the Atlantic, giving the Allies a fighting chance. If the British capture them, they'll rot in jail. But if the Nazis find them, it's game over. Can the outnumbered band of mavericks do the impossible and cheat death?—Nick Riganas

Late 1941. Britain is on the brink of defeat against Nazi Germany, her Atlantic supply line being threatened by German U-Boats. An Italian cargo ship with munitions vital to the U-Boats' functioning is anchored in port on a neutral West African island. A top secret mission, coming from Winston Churchill himself, is launched to destroy the ship. The methods used are as unorthodox as the people undertaking it.—grantss

In late 1941, Germany controls the Atlantic with their U-Boats which inflict heavy damages on any merchant ships passing from US to UK. The movie starts in 1942 with Gus and Anders on a sailboat, boarded by a German naval party. The German captain (Tim Seyfi) is offended by Gus and Anders drunk playboys act and orders that the sailboat be set on fire with kerosene. The German sailors discover armed men hiding in the bowels of the boat, who open fire. Anders slashes the throat of the German captain, and the boarding party is massacred. The German crew came from a destroyer nearby. Freddy is a diver, who had set explosives to the hull of the destroyer. As the destroyer starts firing on the sailboat, the explosives go off and the destroyer sinks.

During World War II the United Kingdom is struggling to halt Nazi Germany's attempts to take over Europe, with London regularly suffering bombing runs at the hands of the Luftwaffe. Their supply and aid ships are constantly sunk by German submarines in the Atlantic. As a result, the UK is starved of munitions, supplies and even men to fight the war. The UK needs 3 million tons of supplies every month and currently they are losing half of that to U-Boats. Till the U-Boats rule the Atlantic, it will be impossible for US troops to come to Europe. The British commander in chiefs recommend Churchill to surrender as they believe they cannot stop an invasion from Germany.

Italian supply ship Duchessa D'Aosta and two tugboats (Bibundi and Likomba) attached to it are stationed on the Spanish-controlled island Fernando Po. The supply ship and the tugboats take care of the entire servicing, rearming and repairing of Hitler's Atlantic U-Boat fleet. The island cannot be bombed as Fernando Po (an Island on the West Coast of Africa), is neutral territory. If the Allied forces attack the island, the rest of neutral Europe will join Hitler in the war.

Brigadier Colin Gubbins (Cary Elwes), with the indirect backing of Prime Minister Winston Churchill (Rory Kinnear), prepares to initiate Operation Postmaster, an off the books black-ops sabotage mission intended to disrupt the Nazis' U-boat resupply operation on Fernando Po. If the operatives are captured by the British, they will be thrown in jail, if captured by the Nazis it will be torture and death.

While SOE agents Marjorie Stewart (Eiza Gonzalez) and Richard Heron (Babs Olusanmokun) depart by train, Gubbins enlists Gus March-Phillips (Henry Cavill) to assemble a ground team to destroy the supply ship and the tugboats. Heron lives undercover on the Island, runs an illegal gambling business and most high-ranking Nazis are his clients. Marjorie will be posing as gold trader from New York. Her mission is to seduce and distract the German CO Luhr. In 44 days, the Nazis will move their operation away from Fernando Po. Marjorie and Heron's job will be to ensure that the Duchessa is filled with supplied, so it is worth blowing up in the first place.

Using the neutral Swedish fishing trawler Maid of Honor, Gus and his allies, Graham Hayes (Hero Fiennes Tiffin) an expert sailor, Freddy Alvarez (Henry Golding) explosives expert, and Danish naval officer Anders Lassen (Alan Ritchson) a killer (the only non-British and or commonwealth subject to be awarded the Victoria Cross), begin the slow sail down the West Coast of Africa to Fernando Po. The sailboat is packed with explosives to destroy the Duchessa.

Upon discovering that SOE saboteur Geoffrey Appleyard (Alex Pettyfer), whom Gubbins had sent ahead on the assumption that Gus would show interest in wanting him on the team, was captured by Gestapo agents, they divert course to a Nazi-controlled section of the Canary Islands (La Palma) for a rescue mission. Gus believes that Appleyard has crucial information needed for the success of the mission. When Gus and his crew sink the destroyer, they are still 18 days away from Fernando Po.

Gus and his crew reach La Palma and find that the Gestapo is already there. Gus knows that if Appleyard is taken away, they will never see him again. Gus decides to launch the offensive in broad daylight. The crew is very calm, composed, and unhurried as they take an entire German military camp armed to the brim. Anders finds Appleyard in the command room, which he attacks all by himself.

Marjorie and Heron steal the suitcase of a German military officer on the train and find the Duchessa's cargo manifest including 400 B grade torpedoes, 5000 tons of diesel, 10,000 CO2 filters. The suitcase is returned before it is discovered as missing. Meanwhile, arriving early on Fernando Po, Marjorie and Heron use the latter's 'illegal' gambling hall to recruit backup for Gus' team while Marjorie seduces Heinrich Luhr (Til Schweiger), the SS commander in charge. Marjorie poses as the buyer for gold that Luhr is selling. Heron plans to throw a party at his club and at the docks to distract the Germans when Gus and his sailboat arrives in harbor. Heron is friends with the Spanish Captain Binea (Henrique Zaga), who bristles at the Germans who are in control of his town.

Gus and his crew are 15 days away from Fernando Po, as they take a longer route to avoid German U Boats closer to the African coast. Binea tells Heron that the Duchessa intends to depart three days ahead of schedule. As the radio messages reaches Gus, he has his crew sail through a British naval blockade of Nazi-occupied West Africa (as this was the only way to cut 3 days off their schedule) despite knowing they will be arrested should their unauthorized mission be discovered. A mole in Gubbins' staff reveals the mission to senior command. Germany starts the aerial bombing of London. A British destroyer acting on the command of the naval high command intercepts the sailboat, but Gus gets lucky when a U-Boat attacks and chases away the destroyer.

Heron and Marjorie meet local Prince Kambili Kalu (Danny Sapani) to get a tugboat to rendezvous with Gus's men outside the harbor. Kambili also provides men to Gus to take over the harbor in case of any resistance from the Germans.

On the night of the intended raid, Heron had 2 parties happening simultaneously, one for officers and one for sailors. There were enough prostitutes at each party to cover every sailor and officer with company. Marjorie and Heron learn that Luhr has had the Duchessa's hull reinforced despite Italian Captain Umberto's (Luca Marrocco) reservations. As such, the Duchessa is unsinkable now. Barely warned of this in time, Gus and Appleyard decide that their best course of action is to hijack the ships and sail them out of the harbor and hand them over to the British Navy.

Appleyard & Anders leads the raid on the Duchessa to capture it, while Gus and Freddy place explosives on the fuel reserves at the harbor to prevent the Germans from following them. Gus and Hayes then take command of the tugboats, which are used to tow the Duchessa out to sea. Freddy set up explosives to blow up the Duchessa's anchor, so the tugboats would be able to tow her out. The fuel dump blows up before the Duchessa is out of the harbor. The sailors leave their party to come out and attack the tugboats with everything they have. Gus's crew combined with Kambili's men fight back and manage to get the Duchessa out to sea.

Although Luhr eventually catches on when Marjorie's act begins to 'slip', the raid is ultimately successful, and Marjorie shoots Luhr in the head. Heron and Marjorie take the last remaining patrol boat in harbor to meet Duchessa at sea. Delivering the boats to a British fleet outside Lagos, the team is nonetheless arrested.

While waiting to be court-martialed, they are saved and recruited by Churchill as part of his 'Ministry of Ungentlemanly Warfare', as their actions have not only severely damaged the Nazis' naval strength, but also have allowed the United States, which recently entered the war following the Japanese attack on Pearl Harbor, to join the European theatre.

A montage of details before the end credits reveal the post operation activities of several protagonists: Gus became a war hero and would helm several similar raids during the war before marrying Marjorie at the start of her acting career. Appleyard would receive several commendations for his role in the mission, much to the king's amusement. Hayes would go on to become a highly accomplished spy notable for surviving a year of Nazi torture without breaking. Lassen would go on to take part in raids outside the group until his death in 1945. Ian Fleming, who had been part of Gubbins' inner circle during this time, would use Operation Postmaster as the inspirational basis for his James Bond novels.