Cobra

As the possibility of a solar storm affecting the U.K. mounts, prime minister Robert Sutherland and his chief of staff Anna Marshall assemble the emergency committee COBRA in an effort to combat the situation.

With the nation in the full grip of the crisis and experiencing the worst blackout in the history of the U.K., Sutherland and his team are forced to work around the clock to restore power; Anna reconnects with Edin.

Sutherland, Anna and Fraser head to one of the worst affected areas; while the prime minister is away, Archie causes problems.

Sutherland's knowledge about his daughter's part in her friend's death is questioned; a new threat rears its head.

Fraser deals with issues in his personal life as the crisis worsens; the prime minister is forced to consider more extreme measures to retain control and maintain order over the country.

Fraser and his team reach the endgame as the crisis reaches a boiling point; the prime minister and Anna fight for their political lives.