Father Brown - Season 6 Episode 4

Mrs McCarthy's friend Freda Knight dies in her sleep at the hospital where Bunty's old nanny Ellen is also a patient but Father Brown feels her death was not natural, especially when the sole heir to Freda's will is also found dead. The father believes that a misguided person may be practicing euthanasia on terminally ill people and hurries to stop them before Ellen becomes the next victim.