Season 1, Episode 7

Ruth Bennett goes missing after being ostracized by her community for having disfiguring marks on her body. Villagers fear that the skin condition is caused by radiation from her father Geoffrey's workplace at the atomic research center. Father Brown later finds Ruth's blood-stained pajamas and suspects that either the 14-year-old's mother, their family doctor, or a plumber with a similar skin condition who's dying of cancer might be behind the disappearance.