Mark and Kristian struggle to start a fire. Jenny and Darren's route down the mountain is made tougher by Jenny's fear of heights. And one team's map-reading sends them miles in the wrong direction.
Dropped naked in the clouds on a freezing mountaintop, strangers Lilly and Luke race against couple Claire and Beau. Luke with life in the wilderness, and vegetarian Claire faces a moral impass.
Ant and Kim go off-route in search of food, whilst Terry and Luke rally together when an injury unexpectedly hinders their progress. Two teams miles off the beaten path - without a thread of clothing!
Couple Sion and Gareth struggle without their gadgets while strangers Dylan and Pete are attacked by insects, in an epic race deep in the Scottish Highlands - completely naked.