We won't say anything specific about this week's episode to avoid spoilers, but here's the BBC synopsis. "Helen and her teenage son Zach don’t really get on, until a random act of kindness brings the mysterious Bob to their front door. He seems to understand their problems and offers to help. But what effect will spending time with this kindly stranger have on their lives?"

With Reece Shearsmith, Steve Pemberton, Jessica Hynes and Noah Valentine.

I had to doublecheck that Jessica Hynes had not appeared in a previous Inside No 9 already. She seems like such a natural fit for the anthology series I'm amazed it took so long for her to be cast. I don't know how friendly she is with Reece Shearsmith and Steve Pemberton but it does feel, looking at her CV, that they have been moving in the same orbit for a number of years and sometimes overlapping. Particularly Hynes and Shearsmith.

Their paths have crossed in some notable productions. Most recently they both appeared in the BBC comedy The Witchfinder, starring Tim Key (who brilliantly starred in the very first Inside No 9, Sardines). Hynes was a regular character while Shearsmith had a bit of a scenestealing role as a sinister witchfinder in the final episode.

They also both appeared in the classic movie Shaun of the Dead (2004), which was directed by Edgar Wright. In fact if you want to go back even further Shearsmith appeared in Wright, Hynes and Simon Pegg's breakthrough TV sitcom Spaced, which ran on C4 from 1999 to 2001. Shearsmith played Mike's long-time rival Dexter.  

They also both appeared in a film called Good Boy, released in 2010, about dog competitions. 

I'm sure there are other links in the Venn Diagram but if I venture any further I might never be able to claw my way out of this rabbit hole. 

Inside No 9, A Random Act of Kindness, Wednesday, May 25, 10pm, BBC Two. 

Picture: BBC