Set in the UK in the immediate aftermath of a mysterious illness which swept the country and left millions dead, the series follows the trials facing a reluctant hero, Dan, and the group he forms around him. They must battle the elements, find sufficient supplies and equipment to survive, and protect themselves against the most destructive force on the planet: other people. Scattered, the group must come to terms with their new reality. They face more danger than they can deal with. They have no idea if they can win the race against time before one of them becomes critical. Meanwhile, back at home a plan is hatched to overthrow a tyrannical rule.