At a fête to raise funds for a Polish school unpleasant mayor William Knight is electrocuted by a microphone. Valentine arrests his long suffering wife Eleanor after a screwdriver is found in her handbag but there are plenty of other suspects, including his young daughter and the secretary he sacked after their affair was discovered, whilst he was also accused of bribery and corruption. As Father Brown solves the mystery a magician at the fête turns out to be the husband,presumed dead, of his housekeeper Mrs McCarthy, who walked out on her decades earlier. Now dying he wants to return to her but she refuses him.

Professor Ambrose is abducted after sending his friend Father Brown an ancient prayer book which supposedly can locate the long disappeared Lannington rosary, said to hold healing powers. Aided by Lady Felicia's chauffeur Sid the priest uses the book to find clues which will lead him to the rosary. There is a deadline as a ransom note arrives, informing the father that the rosary must be delivered to save his friend's life whilst the quest is complicated by the arrival of supposedly reformed criminal Flambeau, who claims he is working as a mercenary for the Papacy to find the relic. And then there is a third party, the actual kidnapper, whom Father Brown must expose.

Ex-colonel Gerard is poisoned after arguing with his nephew Edward. Edward is a former POW from Korea and the colonel claims he has been brain-washed but Edward sticks to his story that Gerard killed his father in order to marry his widow Ada. None of the household - including Ada's brother Rupert and his adopted daughter Jia-Li - seem upset at the colonel's death and each had a motive for murder. Then Father Brown is poisoned - hopefully he can recover in time to unmask the killer.

Father Brown and Lady Felicia are visiting a museum owned by her Egyptologist friend Sir Raleigh Beresford, who has just married the much younger Caterina. Caterina insists on opening a sarcophagus, an action which allegedly carries a curse and some time later she is found dying in a locked room. Sir Ralph's son Leo was having an affair with Caterina, making him a prime suspect, but then Raleigh's adoring secretary Valerie admits to the murder. Father Brown does not believe her and discredits her account before unmasking the real killer.

Sid is engaged with an heiress arrested for her father's murder.

After young baker Alexander Moore dies in an accident, his corpse is stolen from the graveyard and discovered on the premises of undertaker Peter Blackstone, father of Alexander's secret girlfriend Catherine, who is in a feud with his mother Ruth, though he denies taking it. Father Brown realizes that Alexander had faked his own death but that something went wrong. In establishing how and why he uncovers a family secret dating back many years.

Father Brown tries to solve the murder of an authoress with the help of a book she has written.