When the mayor drops dead during his speech at the Kembleford village fete, Father Brown deduces that he was deliberately electrocuted. Meanwhile, Mrs McCarthy's past comes back to haunt her.
Quest roles:
Keith Osborn(Sergeant Albright), Kasia Koleczek(Susie Jasinski), Louise Brealey(Eleanor Knight), Fern Deacon(Kathleen Knight), John Lightbody(Edwin Bloom), Frank Grimes(Frank McCarthy), Sam Crane(William Knight), Emma Hiddleston(Matilda Newell)