In season six of the British espionage thriller, the team are pushed to their limits, as the relationship between British and American security deteriorates and loyalties change. Adam and Ros fight against an emerging terrorist threat, and a deadly virus that could decimate London. This season breakIn season six of the British espionage thriller, the team are pushed to their limits, as the relationship between British and American security deteriorates and loyalties change. Adam and Ros fight against an emerging terrorist threat, and a deadly virus that could decimate London. This season breaks away from the case-by-case episodic format, with one dominant storyline tying all the action together.
