Magna Manor is the chosen filming site for a low budget version of 'The Scarlet Pimpernel.' When the director, Nick Chaney, is found dead, having been decapitated by a very real guillotine, Barnaby and Jones have to sort through the several suspects who had reason to dislike Chaney and see whom had the motive as well as the opportunity to commit the crime.
Could it have been Jed Norris, a former convict who was hired as security for the film set? Or perhaps the miserly producer Jack Braxton or even the local taxi driver who just MIGHT have had a problem with Chaney given that he fathered a child by Chaney's girlfriend.
I found that I didn't care a jot about who killed Chaney or why as I din't like him or any of the suspects at all. Not my favourite episode at all.