Summary: Harry is still missing, and there is one question on everyone's mind: is he dead, or alive? Section D discovers that Harry thwarted a clandestine operation to smuggle weapons-grade uranium into Iraq to justify the war. Now the rogue officers who masterminded the operation want their uranium back, and they are prepared to go to any lengths to get it. If Harry isn't dead already, is it too late to save him?

Summary: The country reaches crisis point when energy supplies are threatened by an explosion at a gas processing plant. With reserves on the verge of running out, Britain is forced to turn to Tazbekstan for help. But in return for energy, the Tazbek Trade and Industry Secretary, Urazov, wants carte blanche to wipe out his enemies on British soil. Is this a price worth paying or can Section D get rid of Urazov in order to secure the deal?

Summary: The pressure is on for Section D when a secret meeting of powerful tycoons is stormed by armed terrorists and eight of the world's richest men are taken captive. But this is no normal hostage situation - undercover at the time, Ros is one the hostages. As events spiral out of control, it looks like no one will make it out alive. Is this the end of the road for Ros?

Summary: Lucas's past comes back to haunt him when his former torturer Darshavin turns up with intelligence about a bomb in London. Harry fears Darshavin still has a psychological hold over Lucas, but Darshavin won't deal with anyone else. With innocent lives at risk Lucas must confront his demons for the sake of the nation, but can he overcome his nemesis in order to save the day or is the pressure too much to bear?

Summary: Harry is puzzled by the sudden death of CIA boss Samuel Walker. Harry is convinced that he did not commit suicide and when another CIA agent dies he begins to think that the deaths have something to do with the power meeting that is being held in Basel. Ros is surprised when her old mentor, Jack Coleville, contacts her and it soon becomes apparent he is involved in what has been going on.

Summary: With the country on the verge of bankruptcy, the government can't pay its national debt payments. Section D is asked to get back more than a billion pounds of illegal earnings from the DeWits Bank. The team has to find out what, or who, Nightingale is after Ruth's investigations into the power meeting at Basel pay off.

Summary: After a Pakistani intelligence officer is murdered in South London, the head of the Pakistani intelligence service talks to Harry and Ros. They learn that there is a planned attack on some Muslims and there are determined to stop an all out war between the Hindu and Muslim communities.

Summary: With India and Pakistan on the brink of war, emergency talks are set up in an exclusive London hotel. Section D faces its biggest challenge yet, as the team tries to avert the first nuclear confrontation since the Second World War. When the Indian delegation abandons the talks, it looks like Nightingale's sinister plan will succeed. Lucas and Ros place themselves in grave danger in a final attempt to defeat Nightingale, but will they make it out of the hotel alive?