As anarchy explodes on the streets and the nation is rocked with night upon night of rioting, Fraser and his team reach the endgame in their mission to get the lights switched back on in the Red Zone. Meanwhile, with his personal life imploding, Sutherland is forced to fight for his political life as Archie finally fires his first shots.
As widespread power outages cause chaos and threaten lives across the country, the COBRA committee comprised of the UK's leading experts and politicians, gathers to find a way to turn the lights back on.