The members of a society that watches Venus are dying one by one from something that turns them completely white, so Steed joins them to flush out the culprit while Peel chases a light that seems related to the killings.
The executives of several ceramics companies are being driven crazy or killed by fear. The trail leads to a consulting company with some unusual techniques for helping their clients beat their competition.
Two spies have obtained information about a secret missile base which they are passing to the other side, via a person known as Captain Caruso, whom the Avengers are charged to locate. In the event the good Captain turns out to be a trained parrot who possesses a photographic memory . . .
Several businessmen have been killed, the murderer having apparently clawed them to death so that the initial suspect is an author who owns a bird of prey and had a grudge against a victim who ran a publishing house. However, the discovery of a comic called 'The Winged Avenger' featuring a super-hero is found by the latest victim. And could the invention of Professor Poole, boots that allow the wearer to climb walls and scale ceilings, be involved?
Five years after a mine disaster, Mrs. Peel and Steed are called upon to investigate the spooky goings-on at the local inn. The ghost of the 16th Duke of Benedict, who was reputedly lost in the mine disaster, has been seen wandering the area and Emma joins SMOG and FOG in a ghost hunt. The Duke's ghost supposedly takes Emma with him to his final resting place in the collapsed mine, but Steed descends into the shaft to rescue her. He finds a secret underground city that is being used to stage an invasion of England; the mine disaster was just a cover-up for the plan. ...
Somebody is systematically killing off foreign agents and Steed, who is initially implicated, declares a truce and calls on his Russian opposite number, Nutski. Along with Soviet agents Anna and Ivan the Avengers discover SNOB, an exceedingly English gentlemen's club with murderously patriotic members.
The Avengers "are needed" after reports that a motorist has repeatedly run over and supposedly killed the same person. Their investigations lead them to the country and the top secret Neoteric Research Unit, which is run by the appropriately-named Dr. Frank N. Stone, who has made a startlingly life-like robot of himself, so much so that Steed finds it hard to tell the two Stones apart.
Z.Z. von Schnerk, a mad Teutonic film director of the Erich von Stroheim variety, along with his has-been leading actor and actress, Stewart Kirby and Damita Syn, capture Mrs. Peel in an effort to make a movie about her life and exciting adventures. Unfortunately it is to end with her violent death so Steed has to follow the clues to find her.
Steed is invited to a party on an aeroplane with six other people who include a matador, a cowboy and a circus strong man. As the pilotless , remote-controlled craft takes off, a voice announces that they are bound for a desert island where one of them will be revealed as a super-killer. Mrs. Peel has to work out how to get to her partner as the bodies start to pile up.
Whilst travelling on an express train on a quest to find a missing agent, Steed and Mrs. Peel get caught up in an assassination attempt on the life of the British Prime Minister on the part of a disgruntled and murderous ticket collector. They are helped in their efforts to foil him by Mr. Crewe, an eccentric owner of an abandoned station.
Mrs. Peel is invited to a bridge party at a house on Exmoor but when she arrives she discovers that she has been lured there by a man known as 'The joker'. She had once helped to put him in prison, but he has now escaped and with his two crazy accomplices, subjects Mrs. Peel to a series of lethal tricks and traps as Steed arrives to help her.
Mad scientist Dr. Krelmar is working on a machine that allows two people to swap minds and enemy agents Basil and Lola intend to use it with the Avengers to get them to destroy their network. Basil exchanges personalities with Steed but Mrs. Peel is suspicious that the man who looks like her partner is acting out of character and has to persuade the real Steed what is going on.
Paul Beresford, the brother of Clement Armstrong, the creator of the Cybernauts, blames Steed and Mrs. Peel for his brother's death at the cold hands of his own creations. Aided by Armstrong's assistant Benson, he abducts several scientists who are blackmailed into producing a new batch of Cybernauts. Whilst he is the perfect gentleman towards Mrs. Peel, his aim is to turn her and Steed into human robots.
Sir Andrew Boyd, the British delegate at a European peace conference has a dream in which he is run over and killed by a car. The dream comes true. The Avengers are charged with the safety of his successor, Lord Melford. He too is beginning to have bad dreams, involving a sinister man who turns out to be a member of the Eastern bloc. There is a plot afoot to derail the conference and Steed and Mrs. Peel intend to foil it.
The Avengers go to the dogs as their only lead when $50,000 of stolen diamonds is found in a dead man's stomach. Mismatched Borzoi hairs lead Steed and Emma to a pet cemetery where they take the bite out of the villain's bark.
The hunt for a murdered courier's despatch leads Steed and Emma to a deadly car race with a "shocking" surprise at the finish line. It takes The Avengers to flag down the murderers and apply the brakes to their plans.
A scientist is killed by having been hurled through and embedded in a wall. This is the latest death of a person engaged in the government's Project 90, whose documents can also not be found. When the Avengers investigate they discover a bizarre means of murder whereby the killer can carry an electrical charge to the victim without being electrocuted themselves.
When Mrs. Peel's friend Major Croft goes missing she traces him to the picture postcard village of Little Storping. Unfortunately the entire population are assassins for hire who lure their victims to the village, kill them and then claim that they have never been there. Croft has been killed, along with his valet to prevent them from exposing the sinister secret and Mrs. Peel is next on the hit list unless Steed can save her. Fortunately, she manages to put in a phone call to her 'husband.'
A car carrying two Ministry officials, enroute to investigate the budget overruns on Professor Rushton's latest project, vanishes under escort. Steed goes to investigate, and discovers the hard way where the money has gone; to build a device capable of shrinking anything to a fraction of its normal size. While Rushton has great science- and industry-oriented plans for the device, his assistant Chivers has plans of his own... to make a profit, and dispose of anyone in his way. Steed, inches tall, manages to telephone Emma with a warning, but she is captured by a ...