|Series 8, Episode 8|
|Series 08, Episode 08|
|Air Date||23 December 2009|
|Previous||Series 8, Episode 7|
|Next||Series 9, Episode 1|
Pakistan seizes an Indian submarine, raising tensions in the region. Home Secretary Andrew Lawrence arranges for a meeting in London between President Mudasser (Nicholas Khan) of Pakistan and the president of India. Because of the risk of a nuclear exchange, the British prime Minister and the American secretary of state will meet at Chequers to keep a watchful eye on the situation and intervene when necessary. Section D has a week to stop the potential nuclear war because of an ultimatum given by India. Section D is also investigating Nightingale's link to the turn of events.
Unclear as to why Nightingale orchestrated Home Secretary Blake's departure, Harry tests the new Home Secretary by having Ros give him a flash drive that will pass to President Mudasser; if it is given to a Nightingale operative, Tariq will be able to trace its forwarding. Lucas breaks into the home of billionaire Nightingale money man to plant a bug but is intercepted by Sarah, whom Russell Price (Mark Aiken), the head of CIA in Europe and Nightingale conspirator, ordered Sarah to kill.
Sarah offers Lucas a deal to escape to another country where they can reunite but Ros enters the house. There is a fray, and Sarah escapes. A Chinese diplomat (Roger Yuan) who is in the pragmatist camp meets with Ruth in a park to give her information on the disagreement between his camp and the Chinese hardliners regarding the question of an India-Pakistan nuclear war. He is assassinated at the meeting.
Eventually, Tariq traces Sarah's whereabouts; she is brought in after Ros shoots her in the leg; she brought to a hospital and put under guard. In response to Lucas's questioning she explains that the nuclear exchange Nightingale is precipitating is like a forest fire, altering the landscape so seeds can grow. It will eliminate Al Qaeda and the Taliban from Pakistan, which will be reduced to ashes; India will still exist but in a greatly weakened state.
A Nightingale agent kills her guard, and assassinates her. After a brutal fight, Lucas and Ros capture the agent alive. Tariq puts a trace on the agent's phone, who must, as instructed, call in the kill. Section D learns that Price is the lead Nightingale operative. To further ensure that the war will happen, Price and his Nightingale underlings kill an Indian officer, and plant a bomb in her room in the hotel President Mudasser and the Home Secretary are meeting.
When Ros and Lucas find the two, they discover that Nightingale paralysed them. Lucas evacuates the President, who later recovers and orders the release of the submarine. However, Ros fails to evacuate Lawrence in time, and the hotel blows up.