In the gold-tinted prologue, knight Irineus Daninsky (Paul Naschy) duels with and decapitates sorcerer Count Bathory. The Countess Bathory (Maria Silva) and her coven (the count seems to have been the only male member) are interrupted during a black mass seeking vengeance for her husband's death. Before she is burned at the stake, the countess puts a curse on Daninsky's descendants in which one of them will accidentally kill one of her descendants and suffer hellish torments. Centuries later, Waldemar Daninsky (Naschy again) accidentally shoots a gypsy while hunting a wolf. The gypsies summon up the devil who selects Ilona (Ines Morales) to seduce Daninsky and inflict the mark of the werewolf on him. Ilona does so and is then killed by an escaped killer (while the US title emphasized the devil over the werewolf, the Mexican title emphasized this red herring mad killer). Meanwhile, Waldemar has fallen in love with the elder daughter (Fabiola Falcon) of a professor (Eduardo Calvo) from Budapest. When the younger daughter (Maritza Oliveres) sleeps with Waldemar, he turns into a werewolf and kills her. Waldemar's his first few killings are attributed to the killer until his rotting corpse is found. Pretty soon, the villagers are rounding up the torches and pitchforks and hunting the werewolf.

Sporting a better script and special effects than its predecessor LA NOCHE DE WALPURGIS, CURSE OF THE DEVIL is also better photographed, at times evoking the imagery of Hammer Films with Francisco Sanchez's fluid tracking shots, mannered compositions, and more control over the location photography despite intermittently effective library music cues (used to better effect in later Naschy films such as NIGHT OF THE WEREWOLF - review HERE) and - in the case of the English version - some poorly chosen dubbing voices (particularly for Naschy). There is a strong sense of tragedy as both Daninsky (Naschy's characterization in this film is more effectively guilt-ridden and tormented than in some of the other films) as well as Ilona as the countess' descendant are destined to pay for their ancestors' sins and of injustice against the self-righteous characters (from Daninsky's ancestor to the mob of villagers). CURSE OF THE DEVIL will likely appeal more to viewers looking for serious horror thrills rather than the possibly-unintentionally campy fun of WEREWOLF SHADOW.