The students face SOE’s demanding selection process. Known as the Student Assessment Board, this intense four-day course puts the students through a series of physical and mental tests, all with the aim of finding out who has the raw talent required to progress to full training. The programme charts the beginning of SOE, which started with a handful of agents, in an organisation determined to find a way back into Nazi-controlled Europe.

The students are dropped in the middle of the remote Scottish Highlands, where they learn survival skills required for life in the field. Training in the same mountains as 1940s agents, they are schooled in the same techniques which prepared a group of agents tasked with putting a stop to Hitler's atomic ambitions in Norway. In a freezing Scottish lake and on a sheer rock face, some of the students are forced to find previously-untapped reserves of mental and physical strength.

The students are transported to a British Stately home - this is SOE Finishing School - a 1940s spy school which prepared agents for a life living undercover in enemy territory. They learn to pick locks, send coded messages and see some real SOE gadgets, before facing an intense mock interrogation designed to prepare agents for the eventuality of capture, torture and possible execution.

Eight of the original 14 students have fallen by the wayside, leaving just six survivors to undertake SOE’s final scheme – a 24-hour practice mission bringing together all the skills they have learned during training.