Harry holds the key to the secrets, and trusting his natural instincts uses his connections to seek the truth, but will his personal relationships end up compromising the lives of those around him? His loyal team decide to risk it all in order to reveal the enemies true identity, but as the clock ticks down will Sir Harry Pearce, super spy, put his trust in the right person? After narrowly surviving his MI5 disciplinary tribunal, Harry Pearce (Peter Firth) finds his world thrown into turmoil as his past comes back to haunt him, putting his team, the nation and his job in severe danger. A bitter intelligence war has broken out between the CIA, KGB and MI5. Harry and his new team realise that someone is trying to sabotage the planned partnership between Britain and Russia via a series of terror attacks. As a passenger plane hurtles towards London Harry has a decision to make, could the old friend have become the enemy, and the enemy the friend?