When ancient parasites rise from beneath a small town, taking the most fearful and susceptible as hosts, a young trans filmmaker finds herself the only one who can sense the possessed, and rally the resistance before the horror escapes and spreads.

A wearer of a parasitic mask with black magic sheds blood on Halloween. 16 years later, a killer with the same profile slaughters Angel's friend, who then must fight fear, overcome personal struggles and unmask the murderer before someone else dies.