When a group of hoaxsters called the Hellfire Club mix murder with their mischief, Steed and Emma demonstrate a few tricks of their own. The whalebone corset, high laced boots and spiked dog-collar Emma wears as the "Queen of Sin" were designed by Diana Rigg herself, and resulted in A Touch of Brimstone being banned from American TV.

Is a creature that can walk up walls clawing to death ruthless and powerful men? Does it have anything to do with Professor Poole's invention of boots that let you walk on the ceiling, or with cartoon superhero the Winged Avenger?