Carmilla arrives in South Carolina to investigate a woman named Millarca. The only information she has is an address, but Troy, the owner of the house, says nobody named Millarca has ever lived there. He offers to give Carmilla a ride into town, and she later coincidentally visits a restaurant where Laura works. Curious, Laura presses for more details, and Carmilla reveals that Millarca is her mother, whom she never knew.
Carmilla eventually becomes annoyed with the questions and leaves, but Laura stops her to explain that her father once rented out a trailer. Carmilla asks for public records at the police station, but they tell her it will take two business days, a delay that keeps the mystery afloat while the two characters start to grow closer. At Laura’s urging, Troy lets Carmilla stay at the trailer, a space he once rented to Millarca, and the two begin to spend time together. As their bond deepens, Troy warns that Millarca was trouble and implies that his daughter may follow a similar path.
A creeping unease settles over the house as Troy recounts old history. He recalls Millarca’s supposed theft and mentions that she left without paying rent. He urges Carmilla to leave town, hoping Laura won’t become too attached to someone he views as dangerous. Meanwhile, Laura’s curiosity grows; she asks questions about her mother and Carmilla’s past, and the two form a tentative connection that teases a more intimate future.
Before Carmilla departs, she checks the police records and learns that Millarca claimed to be involved with Karen, Laura’s mother, in a lesbian relationship. Troy later corroborates this version of events while Laura presses for the full truth. He recounts a painful history: he beat both women when he found them together, and he blames Millarca for Karen’s mysterious illness and eventual death, suggesting she was a vampire who seduced Karen. As the revelations unfold, Laura—who self-injures—tells Carmilla that she now understands her own sexuality. The two women then begin a lesbian relationship that mirrors the past between their mothers, weaving a connection that is as dangerous as it is intimate.
Carmilla confronts the impact of trauma on Laura’s life, urging her to stop self-injury and to reconsider the path she is on. She also vows not to engage in blood fetishism as a substitute for pain, and she encourages Laura to leave town with her. Yet Laura resists, torn between loyalty and the pull of the life she’s always known. Troy grows increasingly suspicious that Laura is still seeing Carmilla and warns that he won’t allow Carmilla to hurt her. Laura insists Carmilla has done nothing to harm her, but Troy’s mistrust boils over when he breaks into Laura’s bedroom and discovers the extensive scars on her skin.
Misunderstanding the situation as vampiric danger, Troy binds Laura to her bed and declares that if Carmilla returns, it will prove she is a vampire. Laura desperately guards Carmilla from his reach, warning her to stay away, but Carmilla refuses to leave without Laura. In a moment of painful clarity, Laura tearfully tells Carmilla that Troy killed Millarca, a revelation that reframes Carmilla’s own history in her mother’s life.
The confrontation escalates to a lethal chase. Troy—who hunts vampires—shoots Carmilla with a bow and arrow as Laura pleads for mercy. Laura stops him from finishing the act with a knife, and she calls the police as Troy retrieves his weapon. Carmilla dies in Laura’s arms, but not before a final, ethereal moment where she glimpses her mother in a telepathic link, hinting that Carmilla may indeed be a dhampir and that Troy’s long-held belief about Millarca has some truth to it. The film closes with Laura fleeing into the night, driving away as the police arrive, leaving behind a trail of questions about family, identity, and what binds two generations to a shared past.
