The Avengers - Season 2 - Eps 18: Warlock
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.
About The Avengers

Title: The Avengers
First Air Date: 1961-01-07
Last Air Date: 1969-05-21
Status: Ended
Rating: 7.729/10 (from 140 votes)
Language: EN
Seasons: 7
Total Episodes: 161
Network: ITV1
Genres: Action & Adventure, Crime, Sci-Fi & Fantasy
Production Companies: Associated British Picture Corporation, Associated British Corporation, ABC Weekend Television
Synopsis
A quirky spy show of the adventures of eccentrically suave British Agent John Steed and his predominantly female partners. Jonathan Steed - an urbane, proper gentleman spy - teams with various assistants throughout the series' run, including Dr. David Keel, Cathy Gale, Emma Peel and Tara King, to repeatedly save the world from diabolical schemes plotted by equally diabolical evil-doers (among them robots and man-eating monsters).
Cast

Patrick Macnee
John Steed

Linda Thorson
Tara King

Ian Ogilvy

William Lucas