In "Dead Letters," we're in Midsomer Barton, where the Oak Apple Week festival is going on. For the last seven years, there has been no Festival Queen, due to the fact that the last Queen died of food poisoning shortly after being crowned.
Now there will be a Festival Queen, but not before the dead girl's mother is found dead. Barnaby and Jones are called in to investigate, and it seems to mean that they will have to go back to the death of the woman's daughter. Especially when there are other murders.
Who is killing these people, why, and how are they connected? Barnaby and Jones have to deal with infidelity, a pedophile, the unpleasant head of the festival, and other unsavory people as they try to figure out what's going on and why.
The role of the doctor, played by Simon Callow, in my opinion is badly miscast. In the story, this man is a chick magnet for the whole village, including a married woman, a sexy female bartender, and a local spinster - that's just who he's been involved with currently. There have been others! The spinster's mother tells her that the doctor can have any woman he wants, why would he bother with her? I have a better question - why would she bother with him? And she has this mad crush on him. Paunchy, not all that pleasant, and looking older than his 57 years, I couldn't figure it out. All I can say is, pickings must be slim there.
Interesting mystery, but fewer than usual clues regarding the real murderer. The denouement was sort of -- wh-what?