Jeffrey Franken, a young man living in Ho-Ho-Kus, New Jersey, works at a power plant and is an amateur scientist who specializes in bioelectricity. He is about to marry his fiancée Elizabeth Shelley. At Elizabeth's father's birthday party, Jeffrey gifts an automatic lawnmower, but during a demonstration Elizabeth is caught in its path and killed in a gruesome accident.
Grief drives Jeffrey to push his knowledge of circuits to the limit, and he begins plotting to rebuild Elizabeth and bring her back to life. He spends long evenings rehearsing with the few salvageable pieces of her, even subjecting himself to self-trepanations with a power drill to steady his nerves. He becomes obsessed with constructing the perfect new body for Elizabeth, planning to harvest the body of a New York City prostitute to anchor his revival.
This plan brings him into contact with Zorro, a muscle-bound, temperamental crack dealer who runs a harsh operation over his territory. Jeffrey finagles a way to rent every one of the prostitutes for a single night, hoping to scout the ideal body parts for Elizabeth. A news report about crack cocaine’s toll on sex workers fuels his chilling confidence: he designs a dangerous “super-crack” and believes it will unlock the transformation he desires. He lures the women to a hotel room under the guise of a “medical examination,” meticulously marking the body parts he wants for Elizabeth. But as his resolve wavers, the women discover the bag of super-crack and, one by one, smoke it, blowing into pieces.
When Zorro bursts in, he is knocked out by the flying head of one of his own workers. Jeffrey hurriedly stuffs the collected parts into trash bags, promising to restore the women once Elizabeth is revived. He then carefully selects the final parts, sews Elizabeth’s head onto the new frame, and summons a storm’s lightning to jump-start life in the reassembled body. The result moves awkwardly and can only repeat phrases spoken by the women who came before; yet it is alive, and Elizabeth—the Frankenhooker—begins wandering New York in search of clients, who end up exploding in electric bursts when they become intimate with her.
Jeffrey goes looking for Elizabeth at a bar, where Zorro is lurking. Hearing Elizabeth mention his name and recognizing the body’s parts, Zorro hammers her so hard that her head nearly detaches from the new form. Jeffrey escapes, drags Elizabeth home, and begins repairs on the neck to secure the head and revive her again.
When Elizabeth awakens, memory returns along with a growing horror at what her body represents and how it was created. Jeffrey tries to explain, but Zorro arrives and decapitates him, dragging Elizabeth away under the claim that most of her new body belongs to him. In the chaos that follows, the spare prostitute parts reanimate and fuse into a number of grotesque monsters that overpower Zorro and pull him into a storage cooler, seemingly to his demise, along with his drugs.
In a final twist, Elizabeth decides to revive Jeffrey using the same method, but the process only works on female bodies. Faced with that limitation, Elizabeth places Jeffrey’s head on a body made from the prostitutes’ parts and brings him back to consciousness. When he awakes, Elizabeth promises they will be together forever, while Jeffrey—now inhabiting a new female form—moans in horror at his unexpected transformation.
