Set in the lush and eerie backdrop of Madeira, the story follows Countess Irina Karlstein, a mute and enigmatic vampire who survives on a diet of human sexual fluids rather than blood. As she seduces her victims, a journalist named Baron von Rathony becomes obsessed with her mysterious allure and starts investigating the series of strange deaths linked to her. The erotic tension between them heightens as he gets closer to uncovering her dark secret. Irina's presence is both captivating and terrifying, leading von Rathony deeper into a world of luxuriant decadence and mortal danger.

Parallel to von Rathony's pursuit, Dr. Roberts, a psychiatrist with knowledge of the supernatural, becomes embroiled in the eerie happenings. The countess's wanderings through foggy forests and deserted manors underscore her eternal loneliness and despair. As the narrative progresses, Irina's duality—both predator and tragic figure—sharpens the emotional intensity of the film. The interplay of exquisite beauty and nightmarish dread propels the story towards its inexorable conclusion, where the characters' fates converge amidst the lingering tension between life and death.