In 1940, college student Paul proposes to his girl friend, Leslie Hollander, in the cemetery where they first kissed. At the same time, vampire Caleb Croft emerges from his crypt, and just as Paul and Leslie begin to kiss, Croft attacks, draining Paul of blood and raping Leslie. Lt. Panzer investigates the crime, and learns that Croft’s crypt is empty and that Old Zack, a drunken vagrant, saw a man run from the scene. Panzer visits a dazed Leslie in the hospital and, upon noting her horrified reaction to a photograph of Croft, deduces that a vampire is at large. Panzer’s partner, Sgt. Duffy, warns him that it will ruin his career to name Croft, who was supposedly killed years earlier by police pursuing him for multiple rapes, as the perpetrator. Meanwhile, Croft is hiding in a housewife’s basement, and soon lures her downstairs in order to kill her. Days later, Leslie is leaving the hospital with her protective roommate, Olga, when Dr. Ford informs her that she is pregnant. Although he warns her that the baby is not normal and urges her to abort it, Leslie, now paranoid and delusional, insists it is Paul’s child. The same night, Panzer is investigating Croft’s crypt when the vampire slams the heavy stone lid on his head and then drinks his blood. Months later, Leslie gives birth to a baby boy who is healthy, despite his curious gray color. The baby refuses her milk and seems certain to die, until she accidentally cuts her finger and notes him eagerly drinking her blood. Soon she is drawing her own blood and feeding it to him in a bottle. Thirty years later, the son, James Eastman, buries his mother and hunts his father, whom he blames for his own and Leslie’s suffering. Knowing that Croft preys on college students, James travels from college to college. In an adult education class on folk mythology, James meets the assertive Anita Jacoby, her demure roommate Anne Arthur, and their teacher, Croft, who now calls himself Professor Adrian Lockwood. During the first class, James draws Croft’s attention by disclosing that he is studying Charles Croydon, a 17th century English nobleman thought to be a vampire. After class, Anne thanks Croft for his passion, and he discomforts her by caressing her cheek and remarking on her resemblance to his late wife, Sarah. Later, at the library, Croft is infuriated by the flirtatious librarian, whom he then kills. Anita invites James to a party at her apartment, which is downstairs from his, but despite her attempts to seduce him with both her dancing and her knowledge of Croydon, James remains uninterested. When Anne returns to the apartment, Anita urges her to cook James dinner at his apartment, and after they leave, considers what Anne has told her about the professor referring to his wife. Realizing that Croydon’s wife was named Sarah, Anita deduces that Croydon, Croft and Lockwood are the same man. While Anne and James find themselves mutually attracted and fall into bed passionately, Croft visits Anne but finds only Anita home. Anita reveals what she knows of Croft’s identity, then demands that he make her a vampire so she can be his eternal bride. When he counters that the relationship would become stale over an eternity, she threatens to expose him, prompting him to slit her throat. Later, Anne leaves James, and returns home, undressing to shower. In the bathroom, as she finds Anita’s body, Croft attacks her, hiding his face. Her screams summon James, who rescues her, although Croft escapes unseen. The next night, James and Anne attend a séance at Croft’s lavish home, along with four other students. Croft leads them in a meditation, during which he senses that one of them is resistant. Calling to Sarah, he instructs his wife to possess Anne so they can once again be together. It is Anita’s voice, however, that soon emanates from Anne’s lips, declaring that she, too, has been summoned. Croft, realizing that James has brought Anita’s spirit, commands Anne to cast her out, and Anne struggles to do so, then passes out. As James carries Anne upstairs, Croft attacks and kills the other students. Hearing the shouts, James runs downstairs and fights Croft viciously. At one point, Croft overcomes James and goes after Anne, but James once again rescues her and admits to Croft that he is the vampire’s son, vowing to destroy him. After a prolonged battle, James drives a stake through his father’s heart, but as soon as Croft dies, James contorts in pain. As Anne watches in horror, James grows fangs and turns on her.