Twenty recruits prepare to enter `Jungle Hell', the toughest phase of SAS selection. First they are tasked with traversing the 'trainasium', suspended 50 feet above the ground. Then they must complete a 200-foot abseil headlong into a waterfall.

The recruits take part in extreme hand-to-hand combat. A breach of camp discipline leads to a 'beasting'. And a recruit gets stranded up a huge waterfall.

In the Vietnamese jungle, the group are tasked with a 200-foot abseil into a dark bat-infested cave. In a bustling market, the recruits must take down an armed gunman in a crowd of civilians. And then they take on each other in a game of murderball.

The remaining 11 recruits face a hostage rescue mission hoping to spring two abducted recruits. The second challenge is a punishing head-to-head team ammunition supply race in the jungle.

The recruits' will to survive is severely tested with an extraction task used in the Vietnam War. Then the recruits must make it through a survival task that requires navigating through the jungle while being pursued by hunters.

The seven remaining recruits are ambushed by a hunter force team behind enemy lines. Handed over to interrogators for questioning, the recruits must endure psychological and physical punishments designed to break their will and force a confession.