Alan Colby is an English racing driver who, along with his wife Denise, Colby, experienced a traumatic car accident a year prior. While physically they recovered, Alan began to face severe emotional struggles; he suffered from mood swings and increasingly violent tendencies that cast a shadow over their relationship. To escape the stress and turmoil, the couple decided to vacation together on the picturesque Côte D'Azur, hoping a change of scenery might bring some relief.
During their holiday, they met Dr. Prade, a psychiatrist from London who quickly became involved in their lives. Denise confided in Dr. Prade about the difficulties in her marriage, which seemed to ignite Alan's anger and frustration. Tensions escalated, culminating in a heated argument, but eventually, the couple managed to reconcile and return to their life in London.
However, Alan's mental state continued to deteriorate. In a shocking and frightening moment, he tried to strangle Denise, revealing the extent of his dark impulses. Terrified and desperate, Denise implored Alan to seek help from Dr. Prade, which he finally agreed to do. During his therapy sessions, Dr. Prade questioned Alan about how he envisioned harming Denise, prompting Alan to share detailed fantasies. He described a gruesome scenario where he would murder his wife by strangulation, dismember her body, and dispose of the parts down their apartment building's waste chute.
As treatment progressed, Dr. Prade concluded that Alan's violent fantasies stemmed from a belief he held—thinking he had already killed Denise during the accident, and that he was reliving that traumatic experience in his mind. Alan, after many sessions, was convinced he was cured, feeling an overwhelming sense of relief. His recovery seemed genuine until he unexpectedly wakes up to find Dr. Prade in his apartment. Alan returns a key that Denise had given him, signifying his ongoing struggle and the haunting memories.
The situation takes a darker turn when Alan, along with Dr. Prade, uncovers clues suggesting that Denise has disappeared. Their suspicions grow, especially after piecing together clues reminiscent of Alan's murderous fantasies. Dr. Prade, concerned for Denise’s safety, tries to persuade Alan to go to a clinic, but they are involved in a car accident en route. In the chaos, Alan manages to escape and makes his way to southern France, where he spots Denise and Dr. Prade on a yacht.
It turns out that Dr. Prade had deceived Denise into taking a holiday while believing Alan was receiving intensive psychiatric care. This betrayal fuels Alan’s paranoia, and he confronts them at Dr. Prade’s house with a gun. Dr. Prade, trying to explain himself, reveals that he has been in the clinic for ten days, which causes Alan to question his own sanity once again. Meanwhile, Denise uncovers troubling evidence—an estimate for repairs to Dr. Prade’s car and signs that he might have murdered his own cat to stage a scene that would deceive Alan into believing he was responsible for Denise’s disappearance.
The emotional climax culminates when Denise confronts Dr. Prade about the truth. Overcome with love for Denise, Dr. Prade makes a desperate attempt to escape using an old gondola lift. Tragically, the cable snaps, and he falls to his death. With this danger eliminated, Alan and Denise are reunited. Nonetheless, the couple is left with a somber feeling, deeply scarred by their ordeal and the revelations that brought their relationship to the brink of destruction.
Throughout the film, themes of mental illness, trust, deception, and the fine line between reality and fantasy are explored in a tense and unsettling manner. The story delves into the complexity of Alan’s psyche and the dangerous repercussions of untreated trauma, ultimately leaving viewers contemplating the fragile nature of the mind and the devastating impacts of hidden fears and secrets.
