A behind-the-scenes look at season four of the series, "Alone,'' during which seven pairs of family members are dropped off miles apart on Northern Vancouver Island; an introduction to the teams includes analysis of what it takes to make the cut.

As their teammates attempt to set up camp, the hikers find that Vancouver Island's terrain is even more punishing when on the move; the island beats one pair into submission, while another grapples with a devastating accident.