As Reg Seekings struggles to cope, he strikes up a friendship with a young Italian boy which ends in yet more horror.

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.

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.

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 return to Britain and are given some time to decompress from the events in Italy. Bill is shocked to hear about the intended role for the SAS in the invasion of France.

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.

With a new mission and the threat of disbandment facing the SAS, an ally is found with a familiar name.

As the SAS advance through Italy, with some assistance from partisans, a commando order issued by Hitler threatens the fate of one of them.

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.

While the SAS find both friends and enemies in Sicily, at Gavi prisoner of war camp, David Stirling receives an unexpected visitor.

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 deep in the desert.