Clawdeen Wolf, half human and half werewolf, has recently started attending Monster High, a school for monsters in all forms. After quickly befriending her classmates Frankie Stein and Draculaura, Clawdeen feels like she has finally found a place where she can truly be herself, or so she thinks. Soon, a devious plan to destroy Monster High threatens to reveal her real identity and Clawdeen must learn to embrace her true monster heart before it's too late.

When a cheer squad practices their routines on Halloween weekend in an abandoned school, they are picked off one by one by an unknown killer.