Marjorie Beaslie, Julie Walters is a housewife in her forties who takes in a lodger named Harold Guppey, Nicholas Hoult who has just wandered into town to look up his long-lost brother. Although she presents as prudish—she no longer sleeps in the same bed as her husband, for “medical reasons”—Marjorie quickly warms to Harold, who is a good twenty years her junior, and the two embark on a clandestine affair. Marjorie insists that Harold address her as “mum,” a detail that adds a troubling oedipal edge to their relationship and unsettles the quiet rhythm of the household.
Joyce, the fourteen-year-old youngest daughter, is a precocious mix of grown-up swagger and childish mischief. She dances between trying to act older, applying makeup and smoking, and retreating into scenes of medieval punishments or giggling at crude words. Joyce is drawn to Harold, and through her teasing she shifts his interest from apathy to curiosity. When she discovers Harold and Marjorie in bed together, she seems to mistake the scene for a private, innocent “bunk up,” and she somehow talks her way into sharing the bed with them. The trio’s tension thickens as Harold and Marjorie press forward with their affair, even as Joyce pretends to sleep and quietly witnesses more than a child should.
A few days later Joyce uses her leverage to coerce Harold into a night at a hotel. Harold’s response is complicated: he intends to maintain distance but ends up seducing Joyce and then withdrawing, leaving a dangerous power dynamic in place. Stanley, Marjorie’s much-older husband, is a one-legged World War I veteran who sleeps in a separate room and remains largely oblivious to Harold’s entanglements with both Marjorie and Joyce, as is the rest of their suburban community.
Harold’s attempt to escape this untenable situation leads him to consider enlisting in the army and chasing a new relationship, but Marjorie resists his departure with emotional blackmail, pulling him back into the household. One day, during a tense picnic with the three of them, Marjorie and Harold’s simmering affair again comes to the fore. After Joyce steps away to play, Marjorie makes a bold move and tries to ravish Harold. Joyce returns just in time, striking her mother with an axe. Harold panics, tries to ferry Marjorie to a hospital, but Marjorie, bloodied, seizes a knife Harold drops and attacks him. Harold fights back and stabs Marjorie to death. Joyce then turns on Harold, and he stabs her as well. In a final, desperate act, Harold stabs himself in the stomach, a claim that he acted in self-defense.
A postscript notes that the real Albert Goozee was sentenced to death for Joyce’s murder, casting a chilling light on the events and their echoes beyond the suburban neighborhood.