Spring 1941. Frustrated with military command's handling of war, Stirling and Lewes formulate a plan to parachute men into the desert, attacking enemy forces from behind the lines.

While recovering in hospital, Stirling ruminates on Lewes's idea to attack the enemy from behind and hatches a plan to get approval for their unit from General Auchinleck at GHQ.

The newly recruited members of the SAS carry out a disastrous and devastating first mission. Determined to prove their strategy will work, they prepare to try again.

As the SAS's reputation spreads among the Axis Italian and German forces, another daring mission results in a shocking and devastating loss to the team.

Paddy initiates the Free French soldiers into some unorthodox training methods, and Stirling leads a raid on Benghazi accompanied by the prime minister's son, Randolph Churchill.

A meeting with Winston Churchill sees the SAS embark on their most daring operation to date. While success sees them achieve official status, Stirling receives some terrible news.

The SAS faces a new mission and potential disbandment, but an ally with a familiar name emerges.

The SAS experiences camaraderie and hostility during their Sicilian deployment. Simultaneously, David Stirling, imprisoned at Gavi, receives an unanticipated guest.

In war-torn Italy, an SAS commando confronts a harrowing fate decreed by Hitler's cruel Commando Order while fighting alongside the partisan resistance.

Reg Seekings forms an unlikely bond with an Italian child, but their friendship takes a dark turn, leading to further tragedy.

As John Tonkin tries to return to the unit, the men of the SAS receive a visit from General Montgomery who can smell drink and heroism.

The SAS returns to Britain, preparing for the invasion of France. Meanwhile, David attempts another escape from Gavi.