Dr. Michael Hfuhruhurr, a brilliant brain surgeon grappling with the grief of losing his wife, has made groundbreaking strides in his field with the innovative "cranial screw-top" technique. His life takes an unpredictable turn when he inadvertently saves Dolores Benedict, a clever and manipulative socialite, after she is struck by his car while fleeing the scene of her husband's mysterious death—an incident that she had orchestrated herself. As Dolores recuperates under Michael's watchful care, they marry, but their marriage soon suffers due to her elaborate ruse of being too sick to consummate their union, frequently complaining of a persistent headache, which only intensifies her emotional games.
Their honeymoon, which doubles as a business trip to Vienna, unfolds against the backdrop of a city gripped by terror from a killer known as the "Elevator Killer." Here, Michael encounters Dr. Alfred Necessiter, an unconventional scientist who has devised a method for keeping living brains in liquid-filled jars—using the victims of the Elevator Killer as his test subjects. As curiously as it may seem, Michael finds himself connected to one of the preserved brains, that of Anne Uumellmahaye, a shared love for singing "Under the Bamboo Tree" igniting a telepathic bond between them. This unexpected relationship blossoms as Michael begins to whisk away Anne's brain to experience her company more fully.
Meanwhile, Dolores, growing increasingly suspicious of Michael, becomes fixated on his unexpected inheritance from his step-grandmother and attempts to revive their once-faltering marriage. However, her plans falter when she uncovers Michael's secret connection with Anne. This discovery prompts her to make a drastic attempt on Anne's life by exposing her brain and eventually trying to burn it in an oven. Furious, Michael expels Dolores from his home, firmly refusing her demands for financial support.
As tensions rise, Michael seeks the guidance of Necessiter, who reveals that the preserved brains have a limited lifespan, with Anne being his longest-living specimen. Faced with urgency, Necessiter proposes a daring solution: transplanting Anne's brain into the body of a recently deceased woman. Michael obsessively searches for the ideal recipient, ultimately considering Fran, a prostitute with a notoriously shrill voice, but is thwarted by his own moral principles. In a surreal turn of events, he stumbles upon Dolores's corpse in an elevator only to realize that her murderer is Merv Griffin, the notorious Elevator Killer.
With the authorities hot on the trail, Michael seizes the chance to take Dolores's body for his bold plan, seeking a dramatic end to their tumultuous relationship. His journey takes a frantic turn as he rushes Dolores's remains to Necessiter's lab, but they are interrupted by the Austrian police, who suspect Michael of reckless driving. Despite his frantic attempts to prove his sobriety, the situation spirals into chaos when it becomes clear that Dolores is actually deceased and not inebriated.
After a dramatic high-speed chase, Michael arrives at Necessiter's laboratory, where the doctor successfully transplants Anne's consciousness into Dolores's lifeless body. This shocking event unfolds before the very police officers who had just cleared Michael's name. However, as unforeseen complications arise, Michael suffers an electrical shock from the equipment, plunging him into a deep coma.
Weeks later, Michael awakens to find Anne now inhabiting Dolores's body, bringing with her a surprising new trait: a compulsive appetite leading to significant weight gain. Yet, Michael's affection for Anne remains steadfast, and they exchange vows in a heartfelt ceremony.
In a chilling post-credits message, viewers are warned to remain alert—Merv Griffin, the infamous fugitive, has yet to be captured. If you should encounter him, it is imperative to inform the authorities without hesitation.
