Agent Borowski has been brainwashed by the enemy, but between moments of multiple-personality disorder he tells Steed that three 'doubles' have been created. Steed tracks down one likely replacement to a holiday camp, but then discovers that he, himself, is about to be replaced.

The Director of Operations (Disco) of the Nutshell, a subterranean World War III bunker, tells Steed and Cathy that Big Ben, a file giving details of all their double agents, has been copied. Security cameras point to a young girl, but she is later found dead. Evidence implicates Steed, and Disco orders that he be apprehended.

At the reading of the will of Wrightson, Steed's former batman, the man's family are shocked to discover his estate is worth a fortune. Steed and Cathy set out to find out where a twenty pounds per week draughtsman acquired such a huge amount of money, and whether it was legal.

Michael Dyter, the newly elected MP for South-East Anglia is shot shortly after making his acceptance speech in which he had threatened to expose a major scandal involving the government. Steed knows that the subject of this was the recent theft of a nuclear warhead near London. So was Dyter killed to keep him quiet, and if so, by whom?

Steed's trap for criminal mastermind J.P. Spaggs involves a brilliant plan to steal a million pounds in gold bullion. But when two detectives arrive at Steed's flat and arrest Cathy for Spagge's murder things don't seem to be going to plan.

The cornea grafts that will, hopefully, restore the sight of blind millionaire Marten Halvarssen fascinate Steed: they're rumoured to be coming from a live patient, one Hilda Brauer. Steed suspects that all is not what it seems and so sends Cathy to Switzerland to oversee the operation.

Willis-Sopwoth, a top pharmaceutical firm, is being drained by cheap imitations of its products in foreign markets. The death of a member of staff while investigating the fraud brings Steed and Cathy face to face with a deadly artist and a plot to poison children.

Strange diseases are being reported in various parts of the world, and Steed's suspicion is that somebody has been tampering with the insecticides and fertilisers of United Foods and Dressings. Cathy Gale is captured whilst investigating, and will be the 'guinea pig' for a test on the new strain of bubonic plague.

Steed and Cathy eat at a Chinese restaurant, but, as ever, it's not just for fun: Steed suspects the owner, Mr Lo, of gold smuggling. He also seems to be allied with Army types who are smuggling ammunition to support ex-servicemen.

Invited to spend the weekend at the home of medievel costume expert Sir Cavalier Resagne, Cathy finds herself alone in the house, pestered by a young man who claims to be a film director, and haunted by her past. And where is Steed?

Emir Abdulla Akaba is visiting London for his annual medical, and Steed suspects an assassination attempt. Despite Steed assumming the guise of a chef, the Emir seems to have been poisoned while eating a meal.

An incoming missile attack, which is detected by all but one of the country's early warning stations, proves to be a false alarm. Steed finds himself attending an exclusive New Year's Eve fancy-dress party on a train. The train terminates at a remote, deserted station, and a guest is killed with an arrow.

The disappearance of an albino elephant from Noah Marshall's zoo seems to be linked to Steed's investigation of ivory dust in a gun shop. Steed sets out to rescue Cathy from the tiger's cage, find Snowy and investigate the ivory smugglers.

Bibliotek are a criminal organisation who are fronted as a church. A coming 'Bible Class' will decide who runs Bibliotek. It could be Steed...

Six agents have died on an escape route through Hungary and Austria. Anderson, a friend of Steed's, has also gone missing. Steed finds his friend but is then accused of being a traitor and taken to a brainwashing unit in Scotland run by the Wringer.

After attending the funeral of an old friend in a lonely Cornish village cemetery, Steed discovers a plot to poison millionaires.

One of Steed's colleagues has been murdered, and the subsequent investigation takes Cathy to a top-secret research establishment and Steed to a wine merchants.

Jockeys and stable hands are being trained in the use of firearms and poisons, so Steed delves deep in the murky world of horse racing.

What does Cathy joining a motorcycle gang, two elderly ladies who own a watermill and claim to be witches, and all of the clocks stopping at a local atomic research station have in common? They're all present in Brian Clemen's first great step into the bizarre.

Arabian revolutionary Sharp is visiting Britain and Steed is put in charge of security. He thinks it is ironic that they are now protecting a man they were trying to kill five years before. Two agents were thought to have died during the violent bloodshed in Abarain but now one of them is very much alive.

The opposition believe Steed is responsible for the death of their agent Vinkel. Steed, however, had nothing to do with the murder and, as a show of good faith, agrees to a swap of partners with Keller in a bid to find the real killer.

Soviet-British trade talks are coinciding with the first London concert of the brilliant young pianist, Stefan Veliko. A young girl accuses Veliko of assault, and is then murdered. If someone wants to disrupt the talks by incriminating the pianist, they seem to be going about it in the right way.

The mysterious death of Corporal Craig of the Highland Guards sends both Steed and Cathy undercover into the army ranks. There, Steed finds himself under court-martial and Cathy becomes second in line to the throne.

When an agent investigating radioactivity levels in shellfish is killed in a beach hut fire, Steed and Cathy get involved in the heady worlds of nightclubbing, chess and lobster fishermen.