A cave in of a local canal tunnel under restoration reveals the skeletons of eight individuals. While most of the skeletons are from a cave in when the canal was under construction in the 19th century, one is obviously of a more recent vintage. Dental records identify him as Eric Edwards who was reported missing in 1965. Supt. Barnaby delves into the history of the canal to see if he can find a connection. DS Troy is over the moon when he learns that he has qualified as a Detective Inspector and that there may be a job for him in another county. In what may be his last case in Midsomer, he follows up on an anonymous tip that teenagers are harassing a local hermit, Tom. When one of those teenagers is shot through the head, Barnaby leaves "Inspector" Troy in charge of the case.