Spooks: Season 7

The team step in when a British soldier is kidnapped by al-Qaeda. Meanwhile, an old protégé of Harry's returns to the fold after eight years in a Russian prison - but whose side is he really on?

Convinced that his Russian counterpart in London, Arkady Katchimov, is behind the Al Qaeda bombing that killed Adam Carter, Harry Pearce launches an unauthorized investigation. Their task is to find a non-diplomatic source who would provide then with information on Katchimov's activities. Meanwhile, listeners capture an electronic burst leading them to believe there may be an unidentified Russian submarine in British waters. With Ros Myers now the head of the team, they focus on Alexander Beletsky, a Russian who has a relationship with Katchimov. They conclude that the Russians may be looking to tap undersea communications cables and launch a denial of service attack, thereby disabling the Internet throughout Britain. Lucas North is keen to get back to work but Harry insists that Lucas go through the entire re-integration process before he does so. A good decision given that it appears that North may in fact be working for the Russians.

When a Pakistani agent informs them that there is an Al Qaeda cell planning an attack in London, MI-5 go into action. They already have an agent in place in the terrorist cell which is led by Nadif Abdelrashid. When what is supposed to be dry run turns out to be the real thing, MI-5 track four bombers as they walk through the city to what is their final destination. One by one, MI-5 try to take each of them down before the bombs explode but they aren't entirely successful. Lucas North meanwhile has a flashback to being tortured by his Russian jailers and recalls one of the interrogators asking about an operation known as Sugar Horse. For Harry Pearce alarms bells go off as the operation was one of the most guarded secrets and known only to a very few. He is convinced there is a Russian mole in the senior levels of the intelligence community and turns to Bernard Qualtrough, a retired spy catcher, to help him ferret out the turncoat.

MI-5 is approached by Mohammed Khordad, the number 3 man in Al Qaeda, for a meeting. Under normal circumstances, they wouldn't even think of meeting the leader of a terrorist group but Harry Pearce is convinced that they should look at any opportunity to reduce the threat of attacks. Khordad is keeping his cards close to his chest and insists that they have to trust one another before they can deal. He tells Harry that a bomb will go off at 3 pm that afternoon unless the Home Secretary publicly absolves two suspected terrorists of any wrongdoing. If he can do that, he will then have more important information for him. As the MI-5 team try find the location of the bomb and Harry tries to convince the Home Secretary of the necessity of making a statement, they also have to deal with another problem: the CIA, which also has a interest in Khordad.

Ros goes undercover to flush out a dangerous international financier who wants to bankrupt Britain. Suddenly it's not just the economy, but also Ros's life, that is at risk.

A teenage boy accidentally stumbles upon a government conspiracy and is instantly absorbed into the world of MI5, ending up on the run.

Sugar Horse is revealed to be a network of sleeper agents in Russia. They are there for use only in the direst of circumstances. Just as the West's relations are on the brink - there is much sabre-rattling when the US announces its plans to install its missile shield in former Eastern European countries - two Sugar Horse agents are apparently murdered. All of the evidence points to Harry Pearce who is arrested and is forced to undergo severe questioning. Lucas North travels to Moscow to see what he can learn. A member of the MI-5 team is revealed as a Russian mole and is now desperate to be extracted after killing another member of the team.

With the Russian mole inside MI-5 now in custody, the team tries to decipher the information Lucas North obtained in Moscow. It is apparent that the Russian intelligence service had their own equivalent to the British Sugar Horse network and have sleeper agents across Britain and throughout the various security agencies. Information from the mole indicates that a thermonuclear device will be exploded in central London and offers to reveal the identity of all sleeper agents in the UK if they agree to provide protection and a relocation package. The Russians have issued instructions to kill Harry Pearce and all of the members of Section D so getting to the mole's information will be difficult. Harry decides to meet his Russian counterpart to ensure he knows that they will all die if they don't work together to stop the bombing.