In a small Eastern European village, the mysterious death of Sir Karell Borotyn leaves the locals in fear and speculation. He is found drained of blood in his own home, suggesting vampire activity. The townspeople suspect Count Mora, a sinister nobleman reputed to be a vampire, and his enigmatic daughter Luna. Sir Karell's daughter, Irena, and her lover, Fedor, are thrust into a web of mystery as they try to uncover the truth. Professor Zelen, an experienced occult specialist, arrives to investigate the supernatural claims and dismisses the villagers' hysteria, suspecting more conventional causes behind the crime. He carefully examines clues and scours through ancient texts as he attempts to get to the bottom of this gruesome event.

As Zelen delves deeper, gathering evidence and challenging the superstitions that grip the village, he collaborates with Inspector Neumann, who is determined to solve the case with logic and reason. The tension mounts as strange occurrences continue to plague the community, shrouding it in an atmosphere of danger and fear. Irena becomes increasingly convinced of Mora's involvement, while Fedor shares her growing anxiety. As new revelations unfold, alliances are tested, and rational explanations are sought in a land overshadowed by belief in the supernatural. Meanwhile, the enigmatic charm surrounding Count Mora intensifies the suspense and propels the investigation towards a dramatic confrontation between truth and myth.