The Avengers (1961)

Season 6: Episode 1

Steed's colleague Sean Mortimer comes to see him in a very confused state. He knows there is a traitor in the organization but he has been drugged to put him in an amnesiac state and he can remember little else. Mrs. Peel investigates but she too falls prey to the drug as she and Sean are abducted by bikers. It is down to trainee agent 69, Tara King, to whom Steed is introduced by spymaster 'Mother' to help him save the day.