Red Troop are propelled from a tragic shootout in Iraq to a plane hijack in London, as terrorists fighting for a free Tibet threaten to blow up a passenger flight to Hong Kong. The opening dramatic scene sees the deaths of Trooper Jamie Dow, who had "half his face ripped off". Corporal Ricky Mann who had "fourteen rounds in his back and he didn't see where they were coming from" and Sergeant Pete Twamley who they put "sandbags in his coffin because there wasn't enough to fill a mess tin". Captain Caroline Walshe and Pru Banks also leave the show, apparently dropped from Red Troop by Dempsey. Back at Hereford the selection process is coming to an end, and new recruits are desperately needed as Red Troop is depleting in numbers. The new group of recruits are a very promising crowd, however to Dempsey's disgust, one of them is a woman (current policy in reality is that women are not allowed in the SAS). Becca aims to be the first woman to pass selection. When the terrorists ask for a female pilot, Henno decides to put the wannabe trooper in the front line.

Henno comes face to face with Al-Qaeda when terrorists seize the Italian Consulate. The notorious Al Djouf threatens to blow up a truck using his mobile phone, unless all prisoners held in Guantanamo Bay are released. The SAS attacks and mobile networks are shut down, but Al Djouf has friends on both sides and the clock is ticking towards an explosion in the capital.