The tug of war between honouring personal loyalties and serving a nation inflicts deep wounds in a five-part thriller written by Matt Charman, Oscar-nominated for his original screenplay for the Tom Hanks film Bridge Of Spies. Embattled UK Prime Minister Abigail Dalton (Suranne Jones) welcomes French President Vivienne Toussaint (Julie Delpy) to 10 Downing Street for a crucial summit as tensions escalate between the two nations over how to police their borders. The French solution is unacceptable to Abigail and her party but attempts at diplomacy are derailed when the Prime Minister's medic husband, Alex (Ashley Thomas), is kidnapped and held hostage. The abductors demand that Abigail resigns her position or Alex will be killed. The Prime Minister has never negotiated with terrorists before and she faces an agonising decision that tests her relationship with her daughter Sylvie (Isobel Akuwudike). Meanwhile, President Vivienne Toussaint uses the terrifying situation to her own advantage to press home her domestic agenda.