Avengers [John Steed; Emma Peel]; Karl; Helmut; Agent 77 of the British secret service
John Steed and Emma Peel are having a picnic when it is interupted by two men wearing Roman armor having a sword fight. After one man is hurt Emma and John defeat the other and rush them both to a hospital. The uninjured man (Helmut, a foreign spy) escapes. John finds a clue in the wounded man's clothes and goes to check out where a movie with Roman soldiers is being filmed and is mistaken for an extra. Helmut recognizes him and tries to kill him during the filming of a fight scene. Emma has found out what is going on from the wounded british spy and arrives in time to save John.
Avengers [John Steed; Emma Peel]; the Colonel; Johnson (the scientist); Sammy; Franz; Hans
John and Emma are sent to help protect a scientist that has created a mirage making machine. While the scientist is demonstrating the machine to his assistant it is causing havok in the countryside. Because of the mirages John and Emma end up being chased by a policeman until they arrive at the scientist's home. There they find the foreign agents who are trying to steal the machine. While trying to escape from the agents they end up going through an Army testing ground where they finally capture the agents using the mirage machine.