Peter Kleist (Antonio Cantafore) is an American college student who arrives in Vienna, Austria to take a break from his college studies and to look up his family's history. At the airport, he is greeted by his uncle, Karl Hummel (Massimo Girott), who invites him to stay at his house. Peter asks Karl about his great-grandfather, Baron Otto Von Kleist. Karl explains that the Baron's name still spreads fear among the local people for he was a notorious sadist who tortured and murdered over 100 of the villagers for the sole purpose of watching them die. Karl also tells Peter that the Baron's old castle and former residence is being remodeled into a hotel for tourists. Peter persuades his uncle to take him to the castle.
After a long drive through the countryside, they arrive at the ominous castle on a hill, where they meet with Herr Dortmund (Dieter Tressler) the entrepreneur responsible for the current hotel project. Peter is particularly interested in Dortmundt's beautiful assistant Eva (Elke Sommer), a former college student of Karl's whose job is to ensure that Dortmundt does not make any lasting changes to the castle's architectures. After a brief tour of the castle, Karl invites Eva to his house for dinner.
During the course of the meal at Karl's house, Peter brings up the subject of Baron Von Kleist, much to the consternation of his aunt (Valeria Sabel). Gretchen (Nicoletta Elmi), Karl's young daughter, claims to have actually seen the Baron in the woods near the castle, but nobody listens to her. Peter then produces an ancient document he claims to have found at his grandfather's house back in America. It is an incantation which, if read in the castle bell tower at midnight, will supposedly bring the Baron back to life. Karl warns him off of trying the ritual for a man's obsession with the occult could lead to danger.
Despite this warning, Peter and Eva go to the castle and read the incantation inside the bell tower. Although it is midnight, the bell tolls two o'clock, the same time Baron Von Kleist was murdered by his victims. Heavy footsteps approach from the outside. A terrified Eva tries to convince Peter to recant the incantation, using the alternate spell on the same document. But before Peter can do so, the doors fling open, and the wind blows the parchment out of his hands and into a fireplace. Peter goes outside to investigate, but there is no one there. Eva knows the consequences of what they have done.
Meanwhile, in the deep woods surrounding the castle, the reincarnated Baron emerges from his grave where he was buried there hundreds of years before. The Baron stumbles into the night and pays a visit to a local doctor's office for medical attention. Just as the legend as foretold, he as risen with the same bloody scars that were inflicted on him when he was killed so many years ago. The doctor (Gustavo De Nardo) dresses his strange patient's wounds and is understandably concerned by the terrible condition he is in, When the doctor insists on calling an ambulance, the Baron grabs a scalpel and stabs the doctor to death. Fleeing into the night, the Baron encounters a drunken grave digger, who is also killed.
The next morning, Peter and Eva admit what they've done. Karl insists to them that they are just imaging things and tells them to forget about it. But the Baron secretly enters his castle and kills Dortmundt by hanging him from the castle ceiling. When the body is found by Fritz (Luciano Pigozzi) the caretaker of the castle, the Baron grabs him and takes him down to the dungeon where he kills Fritz by throwing him into a spike-lined coffin. When Dortmundt is found dead, the plans for restoring the castle fall through and the property goes up for auction.
The next day, the castle is quickly purchased by Alfred Becker (Joseph Cotton), a wheelchair-bound millionaire. Despite the fact that nobody knows anything about him or his past, Becker seems amiable enough and offers Eva a job in assisting him to restore the castle to its original condition. She gladly accepts. Later, Eva is attacked in one of the castle corridors by the Baron, only to be saved by the intrusion of Peter. Eve quits her job and decides to make a fresh start elsewhere. That evening, Eva returns to her apartment in town, only to find the disfigured, black-cloaked Baron waiting for her. Eva escapes out a window and runs through the fog-shrouded streets of the town, playing cat-and-mouse with the pursuing Baron. Eva manages to outsmart her pursuer by seeking shelter at Karl's home.
Finally convinced that the Baron is alive, Karl agrees to help Eva and Peter find a way to destroy him. The visit a local medium, named Christine (Rada Rassimov) who conjurs up a spirit from the netherworld for information about the Baron and his resurrection. Christine gives them a magic amulet which will help them, and she tells them that Peter and Eva are the only ones with the power to destroy the Baron for the ones who raised him are the ones who can destroy him. She also informs them that the Baron knows that Peter and Eva have the power to kill him, so he will do everything in his power to kill them before they can do so. After Peter, Eva, and Karl leave, Christine is attacked and killed by the Baron.
Later that day, on her way home from school Gretchen is terrorized by the Baron, who chases her though the woods. But for some reason, the Baron does not kill Gretchen and lets her get away. After taking her to the castle, Gretchen meets with Becker for the first time. Afterwards, she tells her father that Becker is the same man who chased her in the woods. Karl asks how can she know and Gretchen replies that she recognized him by his eyes, which "burn like fire."
Realizing that any man who has the ability to rise from the dead might also have the power to alter his appearance, Karl, Peter and Eva go to the castle to confront Becker, who denies knowing what they are talking about. When he shows them the castle which is now restored, complete with dummies impaled on wooden stakes, the appearance gives the trio the impression that Becker really is the Baron. As Karl, Peter and Eva secretly debate what do to, Becker, no longer pretending to be crippled, rises from his wheelchair and advances towards them. Peter tries to reason with Becker, but he only knocks him out. Karl tries shooting at Becker/the Baron, but he keeps on advances and also knocks Karl out. Eva holds up the magic amulet to try to use against him, but Becker only flings her aside against a wall, knocking her out. The Baron/Becker then takes the three down to his torture chamber.
When the blooded and battered Eva wakes up, she is tied up to a chair and is startled to see Fritz's dead body in the open spike-lined coffin beside her. Becker ties up Karl to a rack to be slowly stretched to death while he ties up Peter and begins torturing him with red-hot pokers. As Eva struggles to untie herself, she accidentally drops the amulet onto Fritz's dead body. A few drops of Eva's blood from her wounds lands on Fritz's body and the amulet itself. Suddenly, the Baron starts to suffer terrible pains and Fritz rises out of his coffin. The secret of how to destroy the Baron finally comes to light: the Barons victims all rise from their coffins, empowered by the magic amulet which is powered up with blood of the ones who raised him (either Eva or Peter). The undead victims whom include Fritz, Dortmundt, Christine, the doctor, grave digger, etc, all attack the Baron and literally rip him limb from limb. Eva manages to untie both Peter and Karl, and the wounded, blood-covered trio flee from the dungeon, and into Karl's car where they drive away from the castle, while the sounds of the Baron's dying screams echo into the night air.