Dr. Mark Steele, a respected neurologist who often uses hypnosis to treat his patients, endures a growing personal crisis as his marriage unravels. His wife Maria Steele is having an affair, living a comfortable life as a doctor’s wife, and when she refuses his plea for a divorce, he realizes he cannot prevail by gentle means alone. After a night of confrontation, he has a dream in which he strangulates his wife, a vision that foreshadows trouble and clouds his judgment.
When Maria leaves for a weekend, Dr. Mark Steele spontaneously drives away from the city. He awakens on Monday in his office to a chilling reality: his memories of the weekend are gone, and Maria has been murdered in a manner that disfigures her face with acid. A button from his own jacket is found near the crime scene, and Mark is plagued by the fear that he himself might be the killer. The sense of guilt deepens as he begins to question his own actions during the blank period.
His nurse, Stella Madden, urges him to keep quiet and not speak to the police until more facts come to light. Meanwhile, the police move quickly and arrest Robert 'Bob' Duval, Maria’s lover, for murder. Detective Inspector Gregg remains skeptical of Mark, convinced that the neurologist may somehow be involved or connected to the crime. To complicate matters, Duval’s disabled wife visits Mark, pressing him to help prove her husband’s innocence.
Duval is convicted of first-degree murder and faces the death penalty, shaking Mark into action. In a moment of guilt and curiosity, he attempts to hypnotize himself to uncover the truth about his possible complicity. The attempt is interrupted by Inspector Gregg, but Stella records the session, capturing crucial details. In the recording, Mark describes meeting his wife at a mountain cabin, a quarrel, and leaving the cabin just as Duval arrives, then returning to his office and slipping into a deep sleep.
Gregg’s investigation continues, and Mark learns that Duval had borrowed $10,000 from Maria to cover gambling debts. A further turn comes when Duval’s bid for a pardon is denied by the governor. Mark speaks with Stella again, who suddenly faints—an event that hints at larger stakes at play. He contemplates hiring another nurse to manage the growing financial strain, and drives Stella to visit her family, a move that raises even more questions for the anxious physician.
Back at the office, Gregg confronts Mark with the emerging web of connections, and Mark resolves to push further by hypnotizing Stella to uncover what she may know beyond what has already surfaced. On the night of Duval’s scheduled execution, Stella succumbs to the hypnotic probe and reveals the full truth: her plan with Duval to obtain the $10,000, and the crucial confession that she killed Maria when Duval tried to return the money. Stella also admits an earlier attempt to burn down the medical office to destroy records, covering up her embezzlement from Mark.
As the final threads come together, Gregg overhears Stella’s confession and arrests her, explaining to Mark that he never truly doubted the doctor’s innocence but needed hard evidence against Stella to secure justice. The case resolves with a sense of cautious relief for Mark, who must live with the knowledge of Stella’s treachery and the emotional toll of the weekend that set these events in motion.
