Amanda (Tane McClure) and her husband Mark (Myles O'Brien), a college professor, appear happily married, though Amanda is tormented by dark, repressed memories and recurring nightmares. Her psychological distress escalates when she catches Mark in an extramarital affair with one of his students, Cynthia. The shock of discovering her husband's betrayal unlocks Amanda's suppressed past, triggering a sinister transformation as she sets out to exact lethal revenge on both Mark and his mistress.