A Criminologist examines a case book on recent, unusual events in the state of Ohio: In Denton, ingenuous couple, Brad Majors and Janet Weiss, attend the November wedding of friends Betty Munroe and Ralph Hapshatt, oblivious to the strange officiating priest and odd looking guests. Although Brad is uneasy when Janet catches the wedding bouquet, he insists that he loves her and they both look forward to their own marriage. After the ceremony, Brad and Janet proceed to a meeting with their old high school science teacher, Dr. Everett V. Scott, but by nightfall their progress is slowed by a fierce thunderstorm and a flat tire. Brad stoutly vows to go for help alone, but Janet points out they have no idea where they are, so should proceed together. As they recall passing a castle-like house down the road, the couple makes their way there, ignoring the warning signs around the property. As they peer up through the rain at a single lit window in the castle, several motorcyclists, many of whom had passed them earlier on the road, roar onto the grounds and disappear around the back. The doorbell is answered by a pale, hunchbacked man who informs the nervous couple that he is a servant, Riff Raff. Inside, Brad and Janet gape at the Gothic design and, hearing sounds of a distant party, learn they have arrived on a special night. Waving away Brad’s request to use a telephone, Riff Raff and his sister Magenta, a maid, escort the couple to a large ballroom where several bizarrely dressed guests dance and sing enthusiastically. A banner across a stage describes the gathering as the Annual Transylvania Convention. Janet swoons over the weird assembly but, recovering, urges Brad to find a telephone. They are interrupted however, by the arrival of a heavily made-up man in an elegant black cape and platform boots who descends from a small elevator to introduce himself as Dr. Frank-N-Furter, a sweet transvestite from Transsexual, Transylvania. Not recognizing Frank, Magenta and several others as the priest and guests at the wedding, Brad and Janet remain transfixed when Frank twirls off his cape to reveal he is wearing a chic black corset, garter belt and hose. Ordering Riff Raff, Magenta and another assistant, Columbia, to see to the drenched couple’s comfort, Frank then invites them up to his laboratory. Startled to be stripped to their underwear, Brad and Janet reluctantly join Frank in the lab as several excited guests line a viewing platform above. Having donned a green lab coat and clutching a pink pair of rubber gloves and glass of champagne, Frank declares that he has learned the secret of life and announces his greatest achievement in biochemical resection. Pulling back a curtain, Frank displays a plaster figure floating in liquid in a large glass case, then throws several switches which send power surging into the figure. The witnesses gasp when moments later the figure rises to reveal a strapping, handsome, blonde-haired young man whom the delighted Frank christens Rocky Horror. Everyone is impressed, but when a jealous Columbia will only admit that Rocky is “ok,” Frank retorts that Rocky was not made for her. Frank then presents the childlike Rocky with several body-building devices and promises to make him a man. Moments later, there is a crash from a deep freeze unit and a man on a motorcycle crashes forth. The man, Eddie, a former delivery boy who Frank once loved, is covered in scars as part of his brain was used to create Rocky. While Eddie drives around the lab lamenting his fall from Frank’s favor, Frank places Rocky in the lift, then, to everyone’s shock, turns on Eddie with an ice pick and stabs him to death. Undaunted, Frank then joins Rocky in his boudoir. Although most of the guests depart, Brad and Janet are invited to remain and placed in separate rooms. To Janet’s surprise, Brad slips into her darkened room and starts to seduce her when she realizes that it is Frank disguised as Brad. Initially shocked, Janet soon finds that she cannot refuse his advances. A little later, Brad is startled when Janet creeps into his darkened room to seduce him, then is horrified to discover that Frank has disguised himself as Janet. Like Janet, Brad is strangely unable to resist Frank’s charms. Meanwhile, Riff Raff harasses the uncomprehending Rocky who, unable to find Frank, runs outside into the pouring rain. Discomfited by the evening’s experiences, Janet goes in search of Brad only to see him on a lab monitor in bed with Frank. Discovering that Rocky is in his water tank quaking and bleeding from Riff Raff’s mistreatment, Janet comforts him and, overcome by Rocky’s physical magnetism, seduces him. When Frank discovers that Riff Raff has tormented Rocky, he whips his assistant as Brad watches. They are interrupted by the arrival of the wheelchair-bound Dr. Everett Scott, who Frank believes investigates UFOs for the government. After Brad acknowledges that he knows Dr. Scott, Frank grows suspicious that Brad and Janet are Scott’s spies. Surprised to find Brad at the castle, Scott insists that he has come in search of his nephew, Eddie. Doubtful, Frank nevertheless calls for an impromptu late night meal for Scott, who now fears the worst for Eddie as he recognizes that Frank and the others are aliens from the galaxy of Transylvania. As everyone dines on a sumptuous roast, Frank reveals that they are eating Eddie’s remains. Sickened, Columbia departs the dining room before Frank throws aside the table to reveal Eddie’s mutilated body. Hysterical, Janet flees to the lab, followed by Rocky and Frank who warns her to control herself. Brad meanwhile escorts Scott to the lab where Frank freezes each of them to the floor. Although unable to move, Scott questions Frank about whether he really has a transducer that breaks up human matter and sends it out into space. Terrified, Janet demands to know if Frank is going to send them into space. In response, Frank orders Magenta to throw the “Medusa” switch which turns Brad, Janet and Dr. Scott into statues. After dressing each nude statue in boas and corsets, Frank places them on a stage and, returning them to live forms, demands that they perform a cabaret number. Columbia joins them once the curtain opens, revealing a large radio tower and swimming pool in which everyone but Scott throws themselves. As Scott struggles to break free of Frank’s mesmerizing influence to help the others, they obey Frank’s command of “don’t dream it, be it,” and begin an orgy in the pool. The activity is interrupted by the appearance of Riff Raff and Magenta, dressed in their native costumes, insisting upon returning home to Transsexual immediately. Although Frank professes to long for home, Riff Raff suspects he is reluctant to leave earth and orders Frank to bid the humans farewell. Realizing Riff Raff plans to kill Frank if he interferes with the departure, Columbia screams a warning, but is shot down by Riff Raff’s laser gun. When Frank tries to escape, Riff Raff turns the laser gun on him, to Rocky’s dismay. Wailing over Frank’s lifeless body, Rocky then carries the corpse up the radio tower, his superior body withstanding several laser blasts before the tower collapses, plunging him into the pool. In the stunned silence that follows Riff Raff asserts that none of his now-dead comrades ever liked him. Scott praises Riff Raff for his bold action, prompting the alien to apologize about Eddie before telling the doctor, Brad and Janet that they are free to go. When the trio reaches the road outside of the castle, they watch in amazement as the entire building lifts off and flies off into the darkened sky. Bewildered and shocked by their experience, Brad, Janet and Dr. Scott stumble about in the smoky debris of the house-spaceship. In the present, the Criminologist closes the case book and reflects that, in the face of contact with aliens, the human race remains lost in time and space.