David Sumner, a mild-mannered academic from the United States, marries Amy, an Englishwoman. In order to escape a hectic stateside lifestyle, David and his wife relocate to the small town in rural Cornwall where Amy was raised. There, David is ostracized by the brutish men of the village, including Amy's old flame, Charlie. Eventually the taunts escalate, and two of the locals rape Amy. This sexual assault awakes a shockingly violent side of David.
After securing a grant to study stellar structures, American applied mathematician David Sumner moves with his glamorous young British wife Amy to her natal village of Wakely in the Cornish countryside. Amy’s ex-boyfriend, Charlie Venner, and his cronies, Norman Scutt, Chris Cawsey and Phil Riddaway, immediately resent the meek outsider who has married one of their own. Scutt, a former convict, is privately jealous of Venner’s past relationship with Amy, as well. David also meets Venner’s uncle, local drunkard Tom Hedden. Hedden’s flirtatious teenage daughter seems attracted to Henry Niles, a mentally deficient man hated by the entire town.
The Sumners rent an isolated farmhouse, Trenchers Farm, and hire Venner, Scutt, Cawsey and Venner’s cousin to repair its garage. Tensions in their marriage soon become apparent. Amy criticizes David’s condescension towards her and his escape from the volatile, politicized campus, thereby suggesting that cowardice was his true reason for leaving the US. He responds by withdrawing deeper into his studies, ignoring both the hostility of the locals and Amy’s dissatisfaction. His aloofness results in Amy’s attention-gathering pranks and provocative demeanor towards the workmen, particularly Venner. David even struggles to blend in with the educated locals, as shown in conversation with the vicar and the local magistrate, Major Scott.
When their dead cat appears hanging in their bedroom closet, Amy claims Cawsey or Scutt are responsible. She presses David to confront the workmen, but he is too intimidated by them. The men invite David to go hunting the following day. They take him to a remote location and leave him there with the promise of driving birds towards him. Having lured David away, Venner goes to Trenchers Farm where he initiates sex with Amy. She resists, but is slapped and eventually relents to the rape. By the end of the scene, she appears to be at least partially consenting. As they lie together, Norman Scutt enters silently, motions Venner to move away at gunpoint and rapes Amy, this time unambiguously, while Venner then holds her down. When David returns, Amy says nothing about what happened, except for a double entendre that escapes his attention…