Cadfael: The Potter's Field

The Set-up: A farmer plows a field for the first time, as the monks led by Prior Robert (Michael Culver) and including Brother Cadfael (Derek Jacobi) follow behind praying for a good yield from the Potter's field. The plowing stops when the farmer hits a snag that stops the plow from continuing, upon which digging it up they discover the body of a dark haired woman.
There is some speculation that the woman is their former potter's wife - the potter who became a monk just one year earlier. The story flashes back to a year earlier and we see the potter at work and his wife who is extremely unhappy with his choice to enter the monastery - angry not only for losing an income, but for losing her man by which she implies over and over again is to say that he is taking sex away from her.
After the potter has entered the monastery and the wife tried one last time to talk him out of it, even as they are shaving the circle on the top of his head, the lord who owns the land the potter's field and hut are on, stops by with food or money and tells the wife he understands for his wife has been sick for years and denied him a woman. This of course leads them to the bedroom.

The Rest: The lord's son who has professed great disdain for the monastery and the monks who inhabit it has suddenly had a change of heart and went to join the monastery at Cambridge. This is revealed days after the wife has disappeared and just as the lord is off to fight for the king, which he said he wouldn't do under any circumstances.
The body in the field is thought by all to be the potter's wife and by all, except Cadfael, to have been murdered by the potter turned monk. But then the lord's son turns up in need of the monks help and produces the wife's ring and said that he got it from just two days earlier. The body is then believed to be that of a woman with a snake oil peddler, until he proves to Cadfael that she is still alive.
Brother Jerome (Julian Firth) is ready to accuse whomever seems most likely, first the potter, then the lord's son. But we learn, as always, that he is wrong, that as always, he has misjudged the clues and signs.

Commentary: What is up with Hugh Beringar (Anthony Green)? Long gone are his first season days of being Cadfael's equal in the search for justice. Now he is the local cop that doubts everything the good brother says, right up until the truth is revealed at the end. In series I through III, he had a sergeant to do that, but with two of the three episodes, i.e. both I've seen so far, are lacking our long-haired, ill-humored sergeant. Beringar's gaol cells have been featured in both of these episodes as well as the grunting, van dyke wearing gaoler.
The show has gone from being a medieval police procedural, er, monk procedural to being a medieval drama. There is no longer a focus on how Cadfael solves the crime, but how he interacts with the people who admit what he suspects.

The Proof: a vial of hemlock