The beloved ecclesiastical sleuth is back! Sister Boniface Mysteries returns for its fourth season, bringing more wit, warmth, and whodunits to audiences worldwide. Set in the quaint English countryside of the 1960s, the series follows Sister Boniface—a brilliant nun with a passion for forensic science, a talent for winemaking, and a trusty scooter for zipping to crime scenes. This season promises fresh mysteries, from puzzling murders to small-town scandals, all tackled with Boniface’s signature blend of sharp intellect and sisterly compassion.

With its cozy yet clever storytelling, the show continues to charm fans by balancing lighthearted humor with intriguing detective work. Whether she’s decoding blood spatter in the lab or trading quips with the local constabulary, Sister Boniface remains one of television’s most endearing crime-solvers. Season 4 delves deeper into her relationships with the quirky residents of Great Slaughter, while introducing new guest stars and unexpected twists that will keep viewers guessing—and grinning.

---

Sister Boniface Mysteries Season 4 cast and characters explained

1- Lorna Watson as Sister Boniface

Lorna Watson shines once again as the titular Sister Boniface, the quick-witted, science-savvy nun whose curiosity is matched only by her kindness. Watson’s portrayal masterfully balances Boniface’s innocence with her razor-sharp intellect, making her an unconventional yet irresistible detective. Her chemistry with the ensemble cast—especially the local police—adds a delightful dynamic to every investigation.

This season, Watson delves deeper into Boniface’s backstory, revealing hints about her life before the convent and her unshakable faith in justice. Whether she’s gently admonishing a suspect or geeking out over a new forensic technique, Watson’s performance remains the heart of the series. Her ability to blend comedy, drama, and a touch of whimsy ensures Boniface stands out in the crowded world of TV sleuths.

2- Max Brown as Sam Gillespie

Max Brown returns as the earnest and occasionally flustered Detective Sam Gillespie, whose reliance on Boniface’s expertise is both a professional boon and a slight blow to his pride. Brown brings a charming everyman quality to Gillespie, making his exasperation with Boniface’s unorthodox methods endlessly entertaining.

Season 4 sees Gillespie grappling with bigger cases—and bigger frustrations—as Boniface’s reputation grows. Brown’s knack for physical comedy and heartfelt moments ensures Gillespie remains relatable, whether he’s bickering with Felix or begrudgingly admitting Boniface was right (again).

3- Jerry Iwu as Felix Livingstone

Jerry Iwu steals scenes as Felix Livingstone, the bright but green constable whose enthusiasm often outstrips his experience. Iwu’s comedic timing and wide-eyed optimism make Felix a fan favorite, especially when he’s fumbling through interrogations or starstruck by Boniface’s brilliance.

This season, Felix faces more responsibility—and more mishaps—as he strives to prove himself. Iwu’s performance adds levity to even the darkest cases, and his evolving friendship with Gillespie and Boniface provides some of the show’s most heartwarming moments.

4- Ami Metcalf as Peggy Button

Ami Metcalf charms as Peggy Button, the bubbly barmaid with a knack for gossip and an uncanny ability to stumble onto clues. Metcalf infuses Peggy with infectious energy, making her the perfect foil to Boniface’s methodical mind.

In Season 4, Peggy’s role expands as she becomes more entangled in investigations—sometimes to Gillespie’s dismay. Metcalf’s playful chemistry with the cast ensures Peggy remains a vital (if unpredictable) asset to the team.

5- Belinda Lang as Mrs. Clam

Belinda Lang is delightfully acerbic as Mrs. Clam, the convent’s no-nonsense housekeeper whose sharp tongue hides a soft spot for Boniface. Lang’s dry wit and impeccable timing make every line a gem, whether she’s scolding the nuns or side-eyeing the police.

This season, Mrs. Clam’s backstory gets subtle nods, hinting at a past as colorful as her present. Lang’s performance is a masterclass in comedic restraint, proving that even the smallest roles can leave a big impression.

6- Sarah Crowden as Miss Thimble

Sarah Crowden brings eccentric warmth to Miss Thimble, the village’s resident busybody with a heart of gold. Crowden’s fluttery delivery and wide-eyed curiosity make Miss Thimble a hilarious yet endearing presence.

Though her theories are often absurd, Season 4 reveals she’s occasionally (accidentally) right. Crowden’s ability to toe the line between caricature and sincerity keeps the character fresh.

7- David Sterne as Tom Thomas

David Sterne is gruff yet lovable as Tom Thomas, the local mechanic with a penchant for conspiracy theories. Sterne’s gravelly voice and deadpan humor make Tom a standout, especially when he’s butting heads with Gillespie.

This season, Tom’s garage becomes an unlikely hub for clues—and comedy. Sterne’s knack for understated humor ensures Tom never feels like a mere stereotype.

8- Miranda Raison as Ruth Penny

Miranda Raison joins the cast as Ruth Penny, a enigmatic newcomer with ties to Boniface’s past. Raison’s poised yet mysterious performance adds intrigue, leaving viewers—and Boniface—wondering if she’s a friend or a foe.

Her chemistry with Watson crackles, setting up a compelling arc that could redefine Boniface’s world.

9- Virginia Fiol as Sister Reginald

Virginia Fiol returns as Sister Reginald, Boniface’s fellow nun and occasional partner in crime-solving. Fiol’s serene yet mischievous portrayal makes Reginald the perfect convent counterpart to Boniface’s zeal.

Season 4 hints at Reginald’s hidden talents, teasing fun surprises ahead.

10- Robert Daws as CC Lowsley

Robert Daws charms as CC Lowsley, the affable coroner whose morbid humor masks a keen mind. Daws’ wry delivery and camaraderie with Boniface make every autopsy scene weirdly delightful.

This season, CC steps out of the lab more often—with chaotic results.

---

Don’t Miss the Heavenly Whodunits!

Sister Boniface Mysteries Season 4 premieres August 19, 2025, on BritBox—prepare for more mysteries, merlot, and mirthful mayhem!