The streets of Zagreb at night are quiet, almost eerie, as a serial predator rumored to be a vampire moves unseen. One evening, Teobold Majer Maro Martinović goes to visit Dr Franz Glogowecz Danilo Lazović in the psychiatrist’s secluded Gornji Grad villa. Teobold claims to be a 16th‑century vampire and says he comes from a bloodline of vampire hunters, a claim that immediately unsettles Franz, who orders him to leave. Yet the allure of the otherworldly is not lost on Barbara Ksenija Marinković, Franz’s young wife, who is drawn to this enigmatic visitor. Barbara follows Teobold and confronts him at the altar near the Stone Gate of Gornji Grad, where he supposedly bites her neck, leaving two small puncture marks that resemble fangs. Even after she participates in a séance and had claimed to be a witch earlier that evening, Barbara finds Teobold oddly fascinating and invites him to visit the villa again once her husband has fallen asleep. On her way back, Barbara imagines she is pursued by the very rapist she fears, only to realize the pursuer is Franz himself.
Meanwhile, the Glogowecz villa is visited by Franz’s estranged uncle Jambrek Glogowecz Zvonimir Torjanac and Jambrek’s somewhat dimwitted son Jurek [Danko Ljuština]. Jambrek’s presence is surprising because Jalža [Semka Sokolović-Bertok], the housemaid who once knew him intimately, is the one who secretly arranges their entry. The night takes a strange turn when Teobold makes an entrance at what he believes to be Barbara’s bedroom window, but ends up clashing with Jurek, who mistakes him for the folkloric Krampus and tears a piece of Teobold’s cloak. Franz discovers the torn material is Teobold’s, and the combination of unexpected relatives, Barbara’s evasive explanation about her neck, and Teobold’s nocturnal visit gradually pushes him toward the belief that vampires might really be at work.
The next day, Barbara escorts Jambrek and Jurek to the Zagreb Zoo, while Franz brings the cloak fragment to his ally, a chemistry professor Branko Bonacci, who identifies the material as extremely old wool. Franz then dives into his family history in the library, uncovering a chilling lineage: seven of his ancestors were staked as vampires in the 16th century, including a woman named Barbara who was burned as a witch. The revelation, attributed to Teobold Majer, makes Franz’s conviction deeper, though Barbara remains skeptical. Jambrek and Jurek pledge to help him prepare to destroy the vampire, turning the hunt into a family mission.
That night, Franz ventures into the Zagreb Botanical Garden to harvest a hawthorn bush for a wooden stake (glogov kolac), narrowly avoiding arrest by a milicioner in the garden Krešimir Zidarić. The following day, Jambrek places an ad in the newspaper offering vampire-killing services, drawing the attention of police inspector Brodski Ranko Zidarić and healer Bjelinski [Zlatko Vitez], who cryptically vow to support him.
A young woman, Asja Jovanović, appears in response to the ad, describing a neck wound like Barbara’s and directing them to the grave of a supposed vampire, Mr Drakulić [Ilija Ivezić], at Mirogoj Cemetery. In exchange for 2000 German marks, the Glogoweczs agree to take on the job. Barbara plays lookout as Jambrek and Jurek dig up Drakulić’s casket, while Teobold roams the cemetery and is spotted by the group just as they are about to break the tomb. The moment of truth arrives when Franz decides to stake the cadaver, only to be interrupted by the young woman and Inspector Brodski, who reveal the sting operation. Frustrated and dispirited, Franz is taken to the Jankomir Psychiatric Hospital for a time.
Franz is eventually released. Back at his villa, Brodski and Bjelinski apologize for the misjudgment and admit there may be truth to his story after all. The film closes with a surprising confrontation: Teobold Majer encounters Drakulić himself, who is still roaming the night streets of Gornji Grad, leaving the audience with the sense that the vampire myth might be more than legend after all.
