10/10 A legendary ex-spy pays a visit to Thames House with a bomb and holds the team to ransom.
First broadcast: 10 Nov 2005
9/10 Harry's stand against the CIA's extradition policy on British Muslims gets him sacked.
First broadcast: 27 Oct 2005
8/10 The team investigate a Soviet investor who the government see as the saviour of the NHS.
First broadcast: 20 Oct 2005
7/10 Adam and Fiona's marriage is tested when she insists on going undercover.
First broadcast: 13 Oct 2005
6/10 A suspect planning a terror attack from prison is released to lead MI5 to other plotters.
First broadcast: 06 Oct 2005
5/10 Harry discovers an ex-MI5 officer's suicide was staged and vows to avenge his murder.
First broadcast: 29 Sep 2005
4/10 MI5 discover that an Islamic terrorist is planning to enter the UK and launch an attack.
First broadcast: 22 Sep 2005
3/10 Adam goes undercover to destroy a far right political party from within.
First broadcast: 15 Sep 2005
2/10 As the hunt for the bomb maker continues, Adam races to save the life of one of his team.
First broadcast: 13 Sep 2005
1/10 A terrorist bomb devastates London. Can MI5 catch the perpetrators before another strike?
First broadcast: 12 Sep 2005