In flashback from a 'Rebecca'-style beginning: Ellen Foster, visiting her aunt on the California coast, meets neighbor Jeff Cohalan and his ultramodern clifftop house. Ellen is strongly attracted to Jeff, who's being plagued by unexplainable accidents, major and minor. Bad luck, persecution...or paranoia? Warned that Jeff could be dangerous, Ellen fears that he's in danger, as the menacing atmosphere darkens.

When Major Badger arrives to escort Amelia Foster and her niece Ellen to church, he warns them that Jeff Cohalan, who has been staying with them, is a dangerous criminal. They find Jeff unconscious in the garage, with the car engine running. Ellen recalls their meeting: On a train to Pine Cliff, a seaside town in California, Jeff encounters Dr. Hartley, who expresses concern about Jeff's recurring bouts of depression. In the dining car, he meets Ellen, who has traveled from Minnesota to visit her aunt, who lives next door to Jeff. Later, at Ben Sheppard's property office, where Jeff works as an architect, Keith Ferris remarks on his colleague's absent-mindedness. Ellen meets up with Jeff on the beach and asks to see Hilltop, his spectacular house, and he uneasily shows her in. Amelia later tells Ellen that Jeff built the house for his fiancée, Vivian Sheppard, Ben's daughter, who was killed in a car accident the previous year, the night before their wedding. When Ellen next calls on Jeff, she finds him preparing to shoot his horse, whose front leg has somehow been shattered. The following week, after Jeff's dog is found dead, Jeff tells Ellen that his favorite rosebush has also died, and shows her a portrait in his home that has faded dramatically since she saw it a week before. Ellen, who does actuarial work for an insurance company, urges Jeff to consider the statistical improbability of so much "bad luck" befalling one person, suggesting that his misfortune was caused by someone trying to destroy him. Ellen decides to investigate, and the next morning, she takes the portrait to an art dealer, who tells her that it could have been faded by exposure to a sun lamp, recalling a similar incident involving a portrait by the same artist. Later, while Ellen is showing Jeff a lab report stating that arsenic was found in the soil under the rose bush, Amelia rushes in and tells Jeff his house is on fire. The next day, Jeff learns that blueprints were missing from an important design proposal, and Ellen suggests that Keith sabotaged his plans. Dr. Hartley calls Ellen to his office and tells her that he believes Jeff is a paranoiac and is unconconsciously committing these destructive acts to punish himself for Vivian's death. After leaving the doctor's office, Ellen is nearly run over by a car similar to Jeff's. Later that night, Ellen follows Jeff outside and sees him siphoning gas out of his car, and the next morning, Jeff is found unconscious. At the hospital, Jeff tells Ellen that he never intended to die, and that he drained the gas tank so that if she did not show up on time, the car would stop running on its own. Upon leaving the hospital, Jeff does research to determine the owner of the other faded portrait, and learns it was Ben. When confronted, Ben admits to tormenting Jeff, whom he blames for killing Vivian. Just then, Ellen bursts into Ben's office with a witness to the accident, who says that Keith, not Jeff, was driving that night. Jeff recalls what happened the night of the accident: Vivian and her married lover, Keith, decided to run away together, and Jeff followed them as Keith drove recklessly along the treacherous 12-Mile Drive. After the crash, Jeff told Keith to take his car and leave, hoping to spare Ben the truth about his daughter's death. Now, in his grief, Ben hallucinates that Ellen is Vivian and tells her that her mother, who left him long ago, was no good either. He pulls a gun and shoots at them, wounding Jeff in the arm before he is subdued. Later, as they are walking on the beach, Jeff declares his love for Ellen.