In the Falklands War, a top secret SAS mission to South Georgia involves flying up the sheer face of a glacier and dropping men on an icy plateau, riddled with crevasses. When the cold winds prove too much – even for the SAS – the helicopters battle through a blizzard to rescue them. Two helicopters crash while flying blind in a snowstorm, but everyone escapes off the glacier, thanks to the remarkable crew flying a helicopter called Humphrey.