The film depicts a story of a looming war between aristocratic vampires and savage, brutal werewolves for dominance in the underworld. In their ceaseless pursuit for survival supremacy, these two factions, the refined vampires and the ruthless werewolves, are always on the lookout for opportunities to eliminate each other, leading to an imminent and explosive conflict.

The story unfolds in the late 19th century, where the vampire Count Dracula has long been entrenched in the ancient town of Transylvania. Dracula has drained the blood of countless humans and is determined to secure eternal life for himself and the descendants of his three vampire brides. Under the sinister influence of Dracula's vampire family, God has promised the Van Helsing family that unless they eliminate Dracula, their souls will not ascend to heaven, as they are tasked with eradicating the evil that Dracula embodies.

十八世纪末期的纽约，警察们还延用古老的办案方式，对罪犯刑讯逼供，年轻的警察伊卡布·克瑞恩笃信科学的办案方式，因此受到市内同行的排挤，被派到一个名叫睡谷，也称作断头谷的小镇办理一起连环凶杀案。断头谷一直流传着关于“无头骑士”的传说，据说，他是一位嗜血而战的黑森林雇佣军，被敌人割去头颅后，他的孤魂一直在断头谷游荡，在月黑风高之夜，他会骑着快马、 拿着大剑将经过此地的行人的头颅割下