Nightkill

Kathy Atwell begins an affair with Steve Fulton, the assistant to her industrialist husband Wendell. Their trysts take place in her hillside home and are secretly audio-recorded without her knowledge. The recordings set up a dangerous web of secrets that will drive the plot forward.

Steve reveals his plan to poison Wendell and impersonate him on a scheduled flight to Washington, D.C. to appear alive. He intends to use the cover of Wendell's death to claim the money and control the situation. Kathy becomes entangled in a plan she does not fully understand.

Steve administers the poison that kills Wendell, while Kathy watches unknowingly. The murder occurs in the house, and Kathy realizes the gravity of the scheme surrounding Wendell's disappearance. The reality of Steve's wrongdoing begins to crystallize for Kathy.

Steve hides Wendell's corpse in a freezer and hands Kathy the key to a locker at the airport, then departs to board the flight that will stage Wendell's impersonation. The setup establishes a cover story that could implicate Kathy as an accessory. The stage is set for a disappearance that Kathy hardly fully understands.

Kathy attends a charity event where she is publicly honored for her philanthropic work. Later, her friend Herbert Childs visits, drunk, after she rebuffs his romantic advances. The social ritual contrasts with the dangerous secrets simmering beneath.

Lt. Donner informs Kathy that Wendell is missing after his secretary reported him. Kathy checks the freezer and discovers Steve's dead body inside, while Wendell remains missing. Monika, Herbert's wife, arrives and immediately suspects Kathy is having an affair.

Monika's arrival at Kathy's home heightens the suspicion of an affair, further complicating Kathy's precarious position. The social circle closes in as the truth feels increasingly imminent. Kathy tries to stay one step ahead of a mounting web of accusations.

Kathy drives to an abandoned mining camp and dumps Steve's body down a mine shaft to conceal the murder. The act marks a decisive break from the initial cover-up plan, yet it also deepens her involvement in the crimes surrounding Wendell's death.

Donner returns that night and questions Kathy about Wendell's disappearance. She grows evasive, fearing the consequences and the escalating danger that could ensnare her further in the scheme. The investigation begins to tighten the net around her.

Kathy books a flight to Denver and, at the airport, overhears a Wendell intercom page and spots a man who resembles him. She is chased by the car that drives Wendell's Rolls-Royce and pursued to a cement plant, where a crash leaves her unconscious and her car hidden behind concrete blocks.

The next morning, Kathy wakes on her living room floor, battered but alive, and calls Herbert, who agrees to visit the next day. The fragile sense of safety she hoped for begins to erode as the reality of the situation sinks in. She braces for further confrontation with those around her.

That night, Kathy finds Wendell's corpse posed at his desk and discovers her pets' gruesome deaths around the house. Donner reveals that Wendell had hired a private investigator to place recording devices in the house to capture Kathy and Steve's affair, presenting damning evidence.

Donner asks for the locker key, and it is revealed that the man she has been dealing with is actually Kelly Rodriguez, the private investigator. Rodriguez has been using his undercover role to terrify Kathy and seize Wendell's fortune.

Rodriguez barricades the door and uses the water heater to scald Kathy, leaving her unconscious. He departs for the airport with the locker money, while a police officer is bribed under the guise of Steve to look the other way.

Rodriguez, posing as Steve, is questioned by the police but buys their silence with hush money, escaping with Wendell's fortune. A severely burned Kathy manages to phone the police for help as Rodriguez disappears with the fortune.