This is really an excellent episode of Jonathan Creek, called Satan's Chimney. During filming at a Scottish castle, an actress is found dead in a locked room. Someone fired a bullet through a plate glass window - and didn't break it. Perfect mystery for Jonathan.
This episode introduces Julia Sawalha as Carla Borrego, an ex of Jonathan's who becomes his new sidekick.
The castle has a few secrets, including a chamber where people have been disappearing since the 1500s -- and, as they learn, are still disappearing. And the victim has a few secrets, too.
As far as the historical inaccuracy, I don't believe Protestants were persecuted in Scotland.
I have to say, I love the show, and I love this episode, but the show lost something when Caroline Quentin left. With her departure, suddenly the scripts started loading up on sexual innuendo (mostly due to Creek's lascivious magician boss).
It's still wonderful, and Alan Davies wonderfully underplays the cerebral and brilliant Jonathan, who knows a good magic trick when he sees one.