MI-5 - Season 9 (2010)

When a highly-skilled trio of Chinese agents arrive in London for 48 hours only, the team must find out why they are here.

Beth and Dimitri go undercover as Home Office representatives in order to protect the American president who is in London for top secret peace talks.

Relations between the CIA and MI5 are stretched after an American drone is hacked in Afghanistan whilst in British care, leading to the loss of American lives.

Lucas North's secret past is revealed as Vaughan raises the stakes in his efforts to get the "Albany" file. Ruth's life is in danger when she follows up a council worker's report of a "dead drop" in a park.

The team face their toughest challenge ever: tracking down Lucas North, their Section Chief, friend and one of the best agents MI5 has ever had.