Father Brown - Season 3 Episode 12

In a village stricken with polio barmaid Sylvia Swann is stabbed to death at the Standing Stones and her friend Ginnie Godden, the last person to see her alive, is arrested. Father Brown finds evidence to link local herbalist Malcolm to the murder site but Malcolm believes that Sylvia was ritually sacrificed to heal the polio victims and asks Father Brown to help him stop any further deaths.