General · EdgepediaOctober 3, 20266 min read

The Beast Must Die

The Beast Must Die is a 2021 British revenge thriller television series adapted by screenwriter Gaby Chiappe from the 1938 novel of the same name by Nicholas Blake, the crime-writing pen name of Poet Laureate Cecil Day-Lewis. Set on the Isle of Wight, it follows Frances Cairnes, a mother who infiltrates the household of the man she believes killed her six-year-old son in a hit-and-run, while Detective Nigel Strangeways investigates the case she is determined to end by murder.¹ The five-part series was BritBox's first original drama commission.²

Key fact	Detail
Source	1938 novel by Nicholas Blake (pen name of Cecil Day-Lewis CBE); previously filmed by Claude Chabrol as Que la bête meure (1969)¹^•³
Writer / director	Adapted by Gaby Chiappe (Their Finest, Shetland, Vera); directed by Dome Karukoski (Tolkien, Tom of Finland)¹
Lead cast	Cush Jumbo as Frances Cairnes, Billy Howle as DI Nigel Strangeways, Jared Harris as George Rattery⁴
UK run	BritBox, five episodes, 27 May to 17 June 2021⁵
US run	AMC and AMC+, six episodes, 5 July to 9 August 2021⁶
Critical reception	86% on the Rotten Tomatoes Tomatometer (21 reviews); Metascore 73 on Metacritic⁶^•⁷
Production	New Regency Television International and Scott Free; shot on the Isle of Wight in autumn 2020 under Covid-19 protocols¹^•²

Spoilers

Plot

After the police investigation into the fatal hit-and-run of her young son Martie is dropped, Frances Cairnes takes matters into her own hands. Posing as a novelist researching a murder mystery, she ingratiates herself with the family of George Rattery, the man she suspects is responsible, and sets in motion a plan to kill him.⁶ She is tracked by Detective Inspector Nigel Strangeways, who has reason to believe his department covered up Rattery's involvement and who is himself suffering from PTSD after the recent death of his colleague, DI Shannon Dixon.⁶^•⁸ When Strangeways discovers Frances living with George and his family, he works both to prove George's guilt and to head off her plans for revenge before anyone else dies.⁶

In the series' final act, George is poisoned, and the closing episodes turn on who administered the poison and on the fallout of Frances's failed attempt at revenge.⁹

Cast and characters

Cush Jumbo plays Frances Cairnes, a woman in her mid-30s who lost her husband in a sailing accident seven years before the story and her son three months before it begins. Billy Howle plays DI Nigel Strangeways, in his early 30s, a self-reliant detective who has always used work to manage his emotions. Jared Harris plays George Rattery, the suspected killer; Mia Tomlinson plays Lena, George's sister-in-law and a suspected passenger in the car on the day of the accident.⁴^•⁸^•¹⁰

The supporting cast includes Geraldine James as Joy, Maeve Dermody as Violet, Douggie McMeekin as Vincent O'Brien, Barney Sayburn as Phil Rattery, William Llande as Martie Cairnes, and Aasiya Shah as Asha James.⁴^•⁵ Nathaniel Parker, one of the series' executive producers, appears in the smaller role of Blount, Strangeways's therapist.²

Adaptation from the novel

Chiappe made two significant changes to the 1938 book. The protagonist, a father named Frank Cairnes in the novel, became a mother, Frances, a change Chiappe considered natural once she decided to update the story to the present day; she also felt that some of the original character's actions, such as grooming a young woman to reach the suspected killer, would sit uncomfortably with modern audiences.² The setting moved from Gloucestershire to the Isle of Wight, chosen because sailing, which matters to the plot, is not there the preserve of the very rich.²

The road to the screen was long. More than 20 years before broadcast, Nathaniel Parker narrated an audio version of the book and later wrote an adaptation script that Jill Balcon, Day-Lewis's widow, rejected as not good enough. After Balcon's death in 2009, her estate offered Parker the rights, and he set up his own company, Pull Yourself Together Productions, to develop the series with Ed Rubin of New Regency Television International.²

Production

The series was produced by New Regency Television International and Ridley Scott's Scott Free, with Sarada McDermott as producer and executive producers including Ed Rubin, Emma Broughton, Marina Brackenbury, David W Zucker, Parker, and Chiappe.¹ Shooting was scheduled to begin in September 2020 but was delayed for months by the Covid-19 pandemic; when filming finally started in autumn 2020, the Isle of Wight was for a time one of the few regions of England under the loosest tier 1 restrictions. Director Dome Karukoski said the protocols made shooting more tense and tiring, but the delay gave extra time to work on the script, and the constraints forced creative alternatives for scenes that could not be shot as planned.²^•¹¹

Karukoski used the island's split character visually, contrasting its touristy image with a darker side of poverty, including children who cannot afford the ferry fares to the mainland.²

Release and reception

The series premiered on BritBox UK on 27 May 2021, with the fifth and final episode airing on 17 June.⁵ In the United States, AMC and AMC+ carried it as a six-episode run from 5 July to 9 August 2021.⁶^•¹² The differing episode counts reflect the two broadcasters' scheduling of the same season.⁵^•⁶

Critics responded well. On Rotten Tomatoes the season holds an 86% Tomatometer from 21 reviews, with the critics' consensus crediting Cush Jumbo and Jared Harris as thrilling combatants in a coiled potboiler; the audience Popcornmeter score is 66%.⁶ Metacritic recorded a Metascore of 73, generally favorable, with 10 of 11 critic reviews positive.⁷ The Guardian praised the cast's uniformly strong performances and the allusive script, particularly the scenes between Strangeways and his therapist.⁷ TV Guide Magazine described the series as a variation on the country-house mystery that is a how-will-she-do-it rather than a whodunit.⁷

On AMC, the first season averaged a 0.03 rating in the 18-49 demographic and 196,000 viewers in live-plus-same-day ratings. A second season, following Strangeways on a different case, was reported to be in development as early as June 2021; as of September 2026 the series had not been canceled or renewed.¹³

References

Initially written Oct 3, 2026 · Reviewed: Oct 25, 2026 · Edited: Oct 15, 2026; Oct 25, 2026; Nov 1, 2026