Sister Boniface Mysteries Season 4 Will Premiere on BritBox This August

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Last Updated on August 13, 2025 by Stefanie Hutson

BritBox has confirmed that a new season of Sister Boniface Mysteries is on the way, following last year’s festive special set around Great Slaughter’s holiday panto.

What Is Sister Boniface Mysteries?

Sister Boniface Mysteries returns for season 4

Sister Boniface Mysteries is a 1960s-set detective drama that grew out of a character first seen in Father Brown. The spin-off centers on Sister Boniface, played by Lorna Watson, a quick-witted Catholic nun who consults for the local police. She rides a Vespa, runs a small wine operation at the convent, and applies chemistry, microscopy and other forensic techniques in a modest but well-equipped lab on the grounds.

As the description might imply, this one falls firmly on the “cozy” end of the cozy/gritty spectrum.

The show is set in the fictional Cotswolds village of Great Slaughter, a postcard-pretty rural community with a parish church, village green, farms and a lively calendar of fêtes and pantos. The village provides the series with a mix of cozy settings and period detail, while the nearby countryside and stately homes regularly figure into investigations.

The core ensemble includes DI Sam Gillespie (Max Brown), a practical lead detective who values Sister Boniface’s expertise, DS Felix Livingstone (Jerry Iwu), whose training and tidy methods sometimes clash with village realities, WPC Peggy Button (Ami Metcalf), an eager uniformed officer finding her feet, and Reverend Mother Adrian (Carolyn Pickles), who keeps a close eye on convent matters. Chief Constable C C Lowsley (Robert Dawes) oversees the force and occasionally introduces new initiatives that complicate Sam’s team. Episodes balance village life, lab work and police procedure as the group tackles everything from theatrical mishaps to countryside scandals.

What to Expect in Season 4

Lorna Watson as Sister Boniface, Ami Metcalf as WPC Peggy Button

Season 4 features eight episodes and moves the timeline into the mid-1960s. New cases range from a bucking bronco gone haywire on a game show set to a killer scarecrow stalking Great Slaughter. CC Lowsley decides the police need team-building exercises, and a weekend away with the sisters turns into yet another murder investigation.

“Sister Boniface Mysteries is a BritBox staple, and we look forward to sharing a new season of crimes, capers, and Sixties shenanigans with our eager audience,” said Robert Schildhouse, President BritBox North America & General Manager BritBox International.

Who Is in the Cast?

Jerry Iwu as DS Felix Livingstone & Max Brown as DI Sam Gillespie

Returning cast includes Max Brown (The Tudors) as DI Sam Gillespie, Jerry Iwu (Sex Education) as DS Felix Livingstone, Ami Metcalf (Silent Witness) as WPC Peggy Button, and Carolyn Pickles (Broadchurch) as Rev Mother Adrian. Guest stars include Les Dennis (The Madame Blanc Mysteries), Katherine Kingsley (The Larkins), Martyn Ellis (Renegade Nell), Mina Anwar (Happy Valley), Ed Birch (The Witcher), and Daniel Laurie (Call the Midwife).

When Does Season 4 Premiere?

Sister Boniface Mysteries Season 4 premieres in the US on BritBox on August 19, with weekly episodes through October 7. In the meantime, you can catch up on previous seasons HERE. From early August – the end of September 2025, you can also catch older episodes on HBO Max as part of their limited-time collaboration with BritBox.

Behind the Scenes

Season 4 is written by series creator Jack Tindall, directed by Paul Gibson, with Dawn Coulson-Beckett as script producer. Executive producers include Neil Irvine for BBC Studios, Robert Schildhouse and Stephen Nye for BritBox International, and Claire Hookway for UKTV.