The title refers to the mythological character in rural England, a presence that appears, frighteningly, at any time. In this story, there is an eccentric old man who seems to have power over animals and whose gaze can stop people in their tracks. The locals also see him as a threat, so when murders are committed, their tunnel vision is directed at him. It is the usual example of someone being unfairly treated for being different. Here, a bunch of punk kids, run roughshod over the woods where he stays. They threaten him and attack him. One day one of them is gunned down. There is no evidence to choose him, other than his oddness. Barnaby shows his true colors when he has compassion for this man. Of course, as others have mentioned, this is the swan song for Sgt. Troy.