Season 3, Episode 10: Season Finale
An informat tells Mi-5 of a possible sarin gas attack against the London Underground during a speech the Prime Minister will make regarding the Iraq War. However, the informant is killed by an Iraqi terror cell led. On Fiona's birthday, the cell leads Danny and Fiona into a trap, revealing that the threat was a distraction to capture the two; Ahmed threatens to kill them unless the Prime Minister withdraws forces from Iraq.
Missed this one? Trying to catch up? Read our recap of this episode here.