MI5 personnel are caught up in a traffic jam in London while escorting the CIA's most wanted terrorist to an arranged CIA handover point, when he is suddenly rescued by armed men on motorbikes. Harry Pearce, the head of Counter-Terrorism at MI5 is blamed for the terrorist escaping. Especially as Harry disappeared shortly after the incident. An ex-agent, Will Holloway, and protégé of Harry's is recalled by MI5 to assist in finding and bringing Harry in. However Harry has disappeared for a reason. Certain that there is a traitor in a senior position in MI5, he enlists the somewhat reluctant Will to help him in uncovering the rat or rats concerned.
