The Emerson family relocates to the seaside town of Santa Carla, where a teenage boy named Michael, his younger brother Sam, and their recently separated mother Lucy settle into a new life with Lucy’s quirky father, known simply as Grandpa. Lucy finds a job at a local video store owned by a magnetic man named Max, who quickly shows an interest in her. Not far away, Sam wanders into a comic-book store run by Edgar and Alan, the Frog brothers, who declare themselves vampire hunters and insist that undead felons have quietly invaded the town.
Meanwhile, Michael is drawn to Star, a striking girl he meets along the lively boardwalk. He also notices Star’s ties to a charismatic gang led by David, a figure who seems to have everything under control—until Michael accepts a dare to keep pace with the gang on their motorcycles. The chase ends at a derelict hotel that once catered to luxury, buried under the sands of an ancient earthquake, where David shows Michael a new, unsettling sight: he can reinterpret ordinary food as something monstrous, and then offers him a strange, red liquid. Star warns that it contains blood, but Michael drinks anyway. The gang takes him to a railway bridge where each member releases themselves into a fog below after dangling over the edge, and Michael, unable to hold on, falls—only to wake up in his own bed the next morning.
What follows is the unmistakable onset of a transformation. Michael grows unnaturally sensitive to light, finds food revolting, and notices his reflection fading away. A growing craving for blood compels him toward danger, and a near miss with Sam is averted only by Sam’s loyal dog, Nanook. With Sam’s help, the brothers begin to suspect that Michael is turning into a vampire, a change that might only be reversible if they can kill the head vampire. The group of Sam, Edgar, and Alan suspects that Max is the mastermind, but the mystery deepens when a family dinner invitation reveals a chilling truth: Max’s own reflection is visible, a sign of his true nature.
David and his followers escalate the danger by revealing their monstrous faces and showing they can fly, murdering partygoers to illustrate what Michael might become. Yet Michael fights the urge to feed. Star confides that she and Laddie, another gang member, have similarly resisted full transformation; David had hoped Star would kill Michael to seal her fate. Resolute, Michael gathers Sam and the Frog brothers for a daylight raid on the gang’s lair, where they stake Marko and rescue Star and Laddie, while David vows to strike back that night.
Prepared for the impending attack, Michael, Sam, and the Frog brothers stockpile holy water, a longbow, and wooden stakes. When night falls, the gang storms the Emerson house. In the ensuing battle, Sam, Nanook, and the Frog brothers eliminate Paul and Dwayne, and Michael squares off with David, choosing not to embrace the change and driving a final blow into David’s body by impaling him on Grandpa’s antler collection. Yet David’s death does not undo Michael’s transformation, revealing that David was not the true head vampire.
Lucy and Max return home from their date, and Max finally admits he is the real head vampire. He explains that because he was invited into their home, he is immune to the conventional tests that expose a vampire’s weaknesses, and he reveals a twisted plan: to form a vampire family and compel Lucy to join them as mother to the boys. To spare Sam from execution, Lucy consents—just as Grandpa crashes through the wall in a truck, ramming Max and pinning him with a fence post, causing Max to explode. With Max defeated, Michael, Star, and Laddie revert to their ordinary selves. Grandpa then delivers the final, sardonic line that caps the night: “One thing about living in Santa Carla I never could stomach—all the damn vampires.”
