Spring 1941. The British Army is losing the war against Germany and the Axis powers, fighting for control of North Africa. Told to stand down after yet another failed operation, Lieutenant David Stirling, an eccentric young officer serving with 8 Commando, finds himself increasingly frustrated with the military authorities and their handling of current strategy.

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.