Senior civil servants, MPs, and intelligence personnel are all dying suddenly of ""natural causes,"" and there seems to be no obvious link. The only lead is the mortally-wounded agent who talks of angels of death that kill from within.

Mason is the paymaster to a group of informants, but all is not what it seems: the informants are a single man. When Mason suspects this, he is murdered by Wallace, who has been lining his own pockets. Steed begins to investigate, and Wallace decides that the only option left is to frame Steed and kill him.

Paris: Steed captures his nemesis, the Unicorn. But when the Unicorn is accidentally killed by his own men, Steed must use all his cunning to avoid open warfare.

An old flame of Purdey's reappears when a missile goes missing from an air display. But what's the connection between that, a visiting Arab envoy, and a spy satellite photographing Buckinghamshire?

When the Avengers foil a drug drop arranged by a Chinese overlord, they find themselves on the run from his men, the Oriental being determined to have their heads on plates.

After Purdey is kidnapped, Steed is given the ransom of Allied attack plans. But has the whole thing been a set up to make the Ministry think Steed is a traitor?

In 1965, a young Russian soldier guns down a Salvation Army Band and escapes only to fall down dead and grow old. In France, in 1977, a young Russian soldier attacks men wearing uniforms. Then a Russian unit is attacking an empty home. After one of the soldiers dies, he also ages. Why are the Russians attacking old targets and then aging? Steed and company are trying to find answers.

The Russian soldiers attacking in France were just the first wave. Two ""K"" agents are the true key to the plan. One ""K"" assassin is killed while assassinating a retired General. Who is the target for the second ""K"" agent and how might this start World War III? Only Steed, Gambit and Purdey can save the world.

Agent X41 (codename ""Scapina"") is the USSR's most effective spy. But a photograph has fallen into the hands of the Avengers which may give a clue to his identity. The trail leads the trio to Toronto.

April 1969: Typhoon Agatha rages causing a new piece of coastline suddenly to appear in Toronto. It's up to the New Avengers to uncover the truth behind it all.

KGB agent Karl Sminsky is recruiting criminals to train as supremely skilled fighters in order to smash Canada's security system. The Avengers find themselves up against a team of supermen.

The trio are on the trail of a mysterious agent ""The Fox."" Although he escapes, he leaves a palm print on the roof of a car owned by the aged Miss Daly and the Avengers must preserve the print to make a positive ID on their target.