The humans attempt to navigate north through lethal open plains while facing thirst and predators.

When rain threatens their fire, the herd faces its greatest fear - a pride of lions in the dark.

Savage landscape takes a toll as the herd struggles with hunger and crosses a croc-infested river.

Two members are injured by a warthog; a new river presents the daunting threat of hippos.

A doctor must be called after hunger has a serious effect on a diabetic member.

Two struggling members must decide whether to tap out or continue with only 32 miles to go.