Patrick McCann, an IRA leader claims to have information about a nuclear attack on the UK mainland, can MI5 trust the IRA enough to give them what they want in return; 36 hours free of surveillance, free to do whatever they wish?

With Tom's family trapped in his house with a bomb, and nothing Tom or the other spooks can do but watch on. There is a huge explosion and the credits begin. However, there is no time to focus on these events as a Serbian warlord has been seen entering the UK vowing revenge for the death of his sons in a NATO bombing raid. Zoe is sent undercover to track him down, and stop any more deaths.