Steed has infiltrated a gang, led by Mason, which is implicated in Peggy's murder. Steed asks Keel to establish contact with a rival gang, and the doctor discovers that Vance's hitman, Spicer, has been sent to kill Steed.

Keel receives a 'phone call from one of his patients, and ends up assuming the identity of her missing husband, a scientist engaged in secret research. Shot in the chest, Keel needs a minor operation - but the anaesthetist has tampered with the oxygen.

Steed, attempting to break a gang of international diamond smugglers, is living in a bungalow near Heathrow Airport which was once owned by a suicide whom One-Ten suspects of involvement. Steed awakens one morning somewhat the worse for drink, when a phone call advises him to check the morning paper; the police are tracking a hit-and-run driver. Steed checks his car. It is damaged, and the front is covered with dried blood.

Frank Preston is released from prison and is intent on reclaiming the hidden proceeds of his robbery. So is Steed, who has been ordered to follow the man. So are a couple of thugs, who kidnap Carol. So is Preston's scheming wife, eager to get her hands on the one hundred thousand pounds hidden somewhere in the sewers.

When Keel attends a health conference in Geneva he is unaware that he is carrying, in microdot form, a vital new medical formula - unaware, that is, until he is arrested for murder.

To stop his daughter seeing suspected conman Jeremy de Willoughby, Sir Thomas Waller has hired arch-criminal the Deacon to 'put the frighteners on'. Steed is on the trail of the Deacon and, with the aid of Dr. Keel, stops two thugs from seriously wounding de Willoughby. They set a trap for the Deacon and the lovers.

An agent has been killed at the secret dockyard where submarines are built. Steed investigates, and finds that a foreign spy has been arranging 'accidents' for him.

Dr Keel, treating the victims of a cyclone struck Mexican village, uncovers a number of food-poisonings; emergency cooking oil is, in fact, hydraulic fluid.

How has a research centre developing radiation-proof material managed to irradiate one of its scientists? Once more, Steed submits himself to scientific testing.

Shareholders in Anderson's, a small-arms manufacturers, are being killed one by one whilst a tycoon plans a take-over. Rifles and other weapons, possibly manufactured by Anderson's, are being smuggled into Africa. Cathy Gale joins the board with a 20 per cent share in order to investigate.

A man involved in a car crash is found to have fifty thousand pounds worth of diamonds in his stomach. Steed investigates the man's joke shop, Big Laugh, and then the offices of multi-millionaire Litoff. The burial of one of Litoff's Great Danes is not quite what it seems.

Steed is entrusted with the safe-keeping of a new fuel formula when its inventor is found in a coma. The scientist had been involved in a black magic circle which leads Steed and Cathy into the world of hexes and magic powers.

A burglar steals two gold-plated eggs from Dr Ashe, not knowing that they contain a deadly virus. The man quickly falls ill, but refuses to indicate where the case containing the eggs is buried.

The Marfia aren't about to let Steed get in the way of their lucrative drug-smuggling operation between Britain and North America, and arrange for him to be assassinated. Steed survives, and tracks his intended killer to a circus, where some of the clowns prove to be anything but figures of fun.

Thanks to the clever briefing of the Lakin brothers a man charged with treason is found not guilty. Mrs Gale believes that Steed is implicated, and contacts the newspapers. Steed threatens her: either withdraw her allegations or pay the consequences. Soon Steed is on trial for Gale's murder.

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.

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?

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.