#’The Beast Must Die’ Transforms a Schoolteacher Into a Manipulator & Murderer

At the start of this intimate six-part thriller, London schoolteacher Frances Cairnes (The Good Fight’s Cush Jumbo, above) is torn apart by a mother’s worst nightmare: Her young son dies in a hit-and-run while they are vacationing on the Isle of Wight. Her grief turns to rage when the police can’t find the driver, and she vows to track down the beast and impose the death sentence herself.

“She has to become many things she isn’t—a detective, a manipulator, a murderer,” explains The Beast Must Die writer–exec producer Gaby Chiappe, who adapted the Nicholas Blake novel. “Part of the joy of Cush’s performance is watching this transformation.”

Frances hides her anguish under an assumed identity and returns to the island to investigate. After some false starts, her No. 1 suspect becomes rich sports-car aficionado George Rattery (Chernobyl’s Jared Harris). To confirm his guilt, and find an opportunity to kill him, she cleverly infiltrates his toxic upper-class English family, becoming a guest in their mansion. There, Frances treads carefully to keep from being found out by George’s snobby, suspicious sister, Joy (Geraldine James), but she also develops a soft spot for his unhappy young son, Phil (Barney Sayburn).

“Viewers face a moral conundrum,” Chiappe says. “Revenge is what she wants, but is it what she needs? Do we want her to succeed or not?”

The Beast Must Die, Series Premiere, Monday, July 12, 10/9c, AMC