1940. With WWII in full swing, and the Nazis in control of Europe, Prime Minister Churchill orders his Economic Warfare Minister Hugh Dalton to create SOE with the directive to "set Europe ablaze"
A Secret Army looks at the early years of SOE's operations in France, where it sent scores of agents to help create and organise resistance to the Nazis, right up to the crucial role they played in D-Day.
In Nazi-occupied Denmark, life goes on almost as normal, becoming known as 'The Whipped-Cream Front'. But the Germans eventually show their true colours - and Danish SOE agents strike back hard.
In 1942 Nazi-occupied Netherlands, young Dutch SOE agent Huub Lauwers is captured by the Gestapo. It sets into motion a calamitous tragedy for both SOE and the Netherlands and one of the espionage world's worst disasters: Der Englandspiel.
SOE agent Bill Hudson is dropped into occupied Yugoslavia in 1941, only to find its people at each other's throats and the resistance dominated by powerful Nationalist and Communist factions who aim to control the country at war's end.
In Greece, SOE finds itself in a similar situation as it did in Yugoslavia, working with powerful forces aiming to rule the country after the war. A dilemma.
After mixed results in the Balkans, SOE scored success after success in Italy with their agents working in concert with local partisans, something that would prove invaluable with the Allied invasion of Italy in 1943.
The last episode of SOE looks at their performance during the Pacific War, where the lightning advance of Japan overwhelmed British colonies in the Far East, focusing on Malaya, where SOE had to work with hostile insurgents to fight Japan.