Edward "Teddy" Bare [Dirk Bogarde] murders his wealthy wife Monica Bare [Mona Washbourne] after she asks her lawyer Phillip Mortimer [Robert Flemyng] to change her will. He stages it to look like an accidental death, asphyxiation while drunkenly attempting to light the gas fire, a crime he has carefully planned to maintain control over her.
The fallout is as coldly calculated as the crime itself. Monica had intended to leave him nothing of significance, instead bequeathing the mansion from an earlier will while placing the bulk of her fortune in a trust for her sister Dora. The elderly maid receives a small £200, a gesture Edward convinces her is payment for wages, effectively keeping her tied to the household without real compensation. The main inheritance hinges on Dora’s demise, a possibility Edward would rather not face but cannot ignore.
An inquest rules the death an accident, yet Phillip Mortimer, the late Monica’s lawyer, harbors doubts about the circumstances. He hints that Dora, who lives abroad in Jamaica, may hold the key to untangling the truth behind the apparent tragedy.
Seeking to secure the fortune and spectacle of a new life, Edward encounters Freda Jeffries [Margaret Lockwood], a lively widow at a seaside hotel. He invites her to stay at the vast house he has inherited, and she becomes friendly with the loyal servant as she settles in. Freda’s presence introduces a volatile mix of affection, suspicion, and appetite for security, and the new couple finds themselves bound by a fragile trust.
Their world expands when they meet Charlotte Young [Kay Walsh], a practical woman whose car has broken down as she scouts houses for an equestrian school. With Edward’s background as an estate agent, he shows her several properties, stoking Freda’s jealousy by highlighting choices that flirt with a future Charlotte might have—money, property, and autonomy.
Late one night, Edward lures Charlotte back to the mansion under a pretense of business and safety. He abruptly reveals he knows that Charlotte is Dora, Monica’s sister, and brazenly admits killing Monica to clear the path for her own money. He presses Charlotte to leave, but she remains cautious. The mood shifts when Freda and the servant return unexpectedly; Freda escorts Charlotte to the door before she drives away.
Edward relays his killer’s confidence to Freda, proclaiming Monica’s murder as a means of securing what he believes is rightfully his. He even hints at using Dora’s death—by tampering with the brakes on her car—to accelerate his plan to claim more wealth. Phillip Mortimer arrives, having heard the confession through the estate’s gate after meeting at the lawyer’s, and the tension surges as a confrontation becomes inevitable.
In a desperate bid to escape, Edward flees in a car, but the path is blocked by Charlotte’s and Phillip’s vehicles. He jumps to another car—only to discover too late that he has taken Charlotte’s vehicle. Panicked and cornered, he loses control and crashes off a cliff, the end of a coldly orchestrated plot that collapsed beneath its own nerve and greed.
Throughout the tangled web of deceit, the film threads themes of manipulation, social climbing, and the perils of an aging patriarch’s grip on wealth, all set against a backdrop of coastal mansions, glittering hotels, and the ever-present tension between appearance and motive.
