Father Brown

The police raid a premises at night and discover a priest near an open safe. He explains that he is replacing money for a parishioner. He is arrested and detained, but released after the bishop confirms his identity.

Outside, Father Brown meets the erring parishioner Bert and convinces him to become a chauffeur for Lady Warren instead of assisting with get-away cars. The arrangement signals Brown's ongoing involvement in high-stakes crime solving.

Brown is selected to travel to Rome carrying a priceless 1,200-year-old crucifix. He remains aware that his rival, the arch-criminal Flambeau, might try to steal the cross.

The voyage continues by sea to France, then by train to Paris. Brown travels with a priest he met on the ship, and in a Paris cafe they realize two policemen are shadowing them. They seize a moment on an excursion bus, leaving the police stranded.

At the catacombs, Brown deduces that the accompanying priest is Flambeau (the ham sandwich clue on a Friday). Flambeau overpowers Brown, steals the crucifix, and leaves Brown tied among the bones. Flambeau then changes disguise and slips past the waiting police.

Back in England, Brown convinces Lady Warren to auction an important silver chess set to lure Flambeau out of disguise. Flambeau arrives as the porter who carries the set away after the bid, then unexpectedly returns it to prove a point. When the police arrive at the door, Brown and Flambeau divert them by emptying a milk van's rear to create space.

Brown researches Flambeau in a library, even breaking his glasses in the process to learn more. He uncovers a link to Fleurency in the Burgundy region of France, setting up the pursuit. This clue redirects the chase toward the continent.

Brown travels to Burgundy after tracing the link to Fleurency. At a wine festival he spots Flambeau, but the thief slips away again among the crowds. Brown prepares for the next move as the chase continues.

The next day Brown finds an old chateau and asks for 'the duke,' only to be told he is not home. He disguises himself as an old woman on a cart of grapes to slip inside the courtyard. Inside, the chateau shows signs of habitation but is ruinous.

Brown discovers a secret door behind the kitchen fireplace and enters a room containing a priceless art collection. Flambeau hands over the stolen cross, then the police arrive and Flambeau flees through a window. The recovered art is seized by the authorities and later displayed in the Louvre.

Back in England, Father Brown delivers a sermon on the Prodigal Son, reflecting on forgiveness and temptation. The case appears resolved as he contemplates the thief's motives. The cross remains secure, and his investigation ends on a moral note.

Flambeau enters the scene again and sits next to Lady Warren, suggesting the chase may continue. The final image ties up the cat-and-mouse dynamic between Brown and Flambeau, leaving their rivalry unresolved.