This paper aims to unveil the underlying religious morality rooted in Puritan ideology as one of the main drivers of the slasher horror narrative. The analysis of iconic slasher films such as Halloween (1978), Friday the 13th (1980) and A Nightmare on Elm Street (1984) demonstrates how these films, often dismissed as simplistic and exploitative, reflect deepseated fears and anxieties which are firmly rooted in the nation's Puritan past. This paper demonstrates how rigid Puritan morality and their conception of sin and punishment are reflected in the slasher horror narrative. Furthermore, these films can be viewed as a reflection of and commentary on the conservative resurgence which occured under the Reagan administration in the 1980s. The analysis highligths the role of the slasher villain who punishes the characters for transgressing moral boundaries, thus enforcing a strict moral code through violence. Conversely, the final girl embodies both purity and resilience, thus emerging as the hero of the slasher narrative; both and adherent to and a true enforcer of the Puritan morality underlying the slasher narrative.