The wife of a diamond merchant is murdered by a group of smugglers trying to wipe out Britain's Diamond Federation. So Steed goes undercover as a dealer, partnered with the widower's former business partner, and Cathy poses as Steed's "life partner".

Your average smuggling storyline. This one had a hard time keeping my attention since it was late when I watched it. The best parts are Steed's "efforts" to make the "marriage" look real.

After Nicky proposes to Jackie, we hear a sound off-camera like that of a cupboard door being slammed shut.

In the chaos of the closing fight scene, the camera moves up to Fenton who is brandishing a gun. Trouble is the angle is wrong and the cameraman has to make a quick adjustment to show us Fenton's face.

  - Courtesy of Wayne Beckett / Stay Tuned

Steed: "Have you ever hurled of a fella called Fenton?"

Steed: "Now look, you carry back to the garden and you carry on as normal." (???)

Steed: (to Cathy) "Probably think you keep a flat for your extra-marital activities."

Cathy: "Still you were lucky enough to go to jail, weren't you?"

Cathy: "Let's hope he doesn't mistalc it for talcum powder then."