Practical jokes are being played on various VIP's causing diplomatic chaos. But when the jokes turn into murder, Steed and Emma investigate the charming John Cleverly Cartney and his modern-day version of The Hellfire Club... And find there's more to the goings-on than mere boozing and debauchery!

This is the series' highest-rated episode ever... And it's easy to see why! Peter Wyngarde is one of the series best villains and there is much erotic happenstance... the highlight being Emma's "Queen of Sin" costume (designed by Diana Rigg, herself)... that this episode was edited before its initial showing in the UK and banned in the US altogether. Thankfully the original version was released on video, although by today's standards it's mild!

Steed and Emma are at the meeting and looking for Cartney. They see the sedan chair and Steed tells Emma to follow it. The next thing we see is Emma descending a very narrow circular staircase. How'd they get that sedan chair down it?

  - Submitted by Don Bell

The snake Emma is holding is a ball python (roughly three feet long). But later as it's crawling around freely, it becomes a boa constrictor (roughly five feet long).

  - Submitted by Francesca Carey

There is a editing error right at the beginning of the show. Cartney pours himself a drink (no chocolates on arm of chair), then we cut to Cartney sitting in front of the TV whilst drinking (chocolates have now suddenly appeared on the arm of his chair), finally we cut to Cartney selecting chocolates which he carefully places along the arm of his chair.

  - Submitted by Christopher Scott

When Steed and Emma pull over after witnessing the ribbon-cutting murder, the camera zooms in for a close-up, but the trees in the (obviously fake) background remain at the same distance.