Alice Armstrong is receiving electric shock treatment for memory loss after her accidental shooting her mother. Six weeks after her mother's death her father Sir Aaron is also found dead from a blow to the head, his hands tied. Suspicion falls on Jim Magnus, the chauffeur and a former petty crook and on Peter Royce, the secretary, who loves Alice and was sacked after telling Sir Aaron not to send her back to hospital. But a conversation with debt collector Eddie Monk informs Father Brown that the dead man owed huge sums of money and another confession suggests that Sir Aaron tied his own hands. With the death solved Alice then recollects that she was not responsible for her mother's slaying.

Father Brown concerns himself with the case of a murdered member of a pagan community.

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.

Father Brown investigates a murder at an outdoor Jester Festival.