S1, E3: August 1944: Nearly a hundred SAS launched a secret operation in Eastern France to help Patton's men reach The Rhine. By its conclusion, more than thirty were missing. In 1945, a mass grave was found containing the executed men. An SAS Investigation Team led by Major "Bill" Barkworth pieced together what had happened. The SAS had been pursued by special action Gestapo commandos and when Patton's men failed to advance, they were marooned. Barkworth also assisted Vera Atkins of the Special Operations Executive, investigating the disappearance of four agents at Natzweiler Concentration Camp. The women had been injected with carbolic acid and their bodies incinerated. At least one of them was still alive at the time...