In 1953,[a] Senator Larson Crockett has led a campaign that managed to make the majority of the country afraid of magic and even outlaw its use. In Los Angeles, Private investigator H. Philip Lovecraft is hired by film star Kim Hudson to dig up dirt on her husband, producer N.J. Gotlieb, who is about to replace her on his latest film with a young starlet with whom he may be having an affair. In secret, Hypolita Kropotkin, Lovecraft's landlady, works for Gotlieb's film studio as a witch, bringing famous writers from history to help with the scripts.
Always beside Gotlieb is warlock Finn Macha, a former private investigator whom Lovecraft knows. When Crocket, Gotlieb and Macha leave the studio, Lovecraft follows them to a mansion in Los Feliz. Before he can learn what is going on in there, an enchanted raven makes him fall asleep with magic. When he wakes up the next morning, everybody seems to be gone.
At the studio, Gotlieb fires Kim, whom he feels only married him because of his wealth and power. Gotlieb is then murdered by magic, and the main suspect is Kim. Distressed, she hires Lovecraft to find the killer and prove her innocence.
Lovecraft asks Hypolita for help. She, in turn, recruits two magic users from her coven. One of them, senses some of Gotlieb's old memories, which lead to a beachhouse. Gotlieb owns the house and someone used magic to clean it of all evidence. Lovecraft returns alone to the Los Feliz mansion, which turns out to be a whorehouse where prostitutes use magic to turn into whatever each client wants.
Lovecraft goes to talk to Kim. Without knowing, he interrupts a meeting between her and one of the mansion's sex workers. Startled by Lovecraft, the prostitute uses magic to steal Kim's car and flees. Later, that same woman is found in the river, dead and turned into a mannequin.
While going to see Kim again, Lovecraft saves her from committing suicide. She has been using a charm like the one the sex workers have to become more conventionally attractive and have a better shot at being a movie star. Lovecraft confesses he used magic precisely once: he hid a bottle on a suspect's boat, and later retrieved it and "poured" out a conversation that enabled him to close his case. However, his target - Macha - believed the evidence was provided by a woman who had been present, and killed her to eliminate her as a witness.
Senator Crockett uses the recent murders to make Kropotkin a scapegoat in his Anti-Magic crusade. Thanks to newly passed Congressional legislation, he has her sentenced to public burning.
Lovecraft confronts Crockett, who brags about being behind the murders with Macha. Knowing one needs to have a cause to gain attention and political power and knowing that he could not go against corporations, Crockett had decided to attack the magical community. Now a major candidate for president, Crockett orders the arrest of both Lovecraft and Macha (whom he no longer needs). Enraged at this double-cross, Macha puts a curse on Crockett.
Before he can set Hypolita on fire, Crockett starts spitting out frogs. His true inner self then bursts out from inside his body, becoming sincere about his real intentions and his disdain for his supporters. During the ensuing chaos (in which both Crocketts are arrested), Lovecraft frees Hypolita and they escape, while Macha is nowhere to be found.
Lovecraft then goes to Kim's, but finds Macha instead. Macha claims to have kidnapped her, wanting Lovecraft to join him. Macha knows that Lovecraft has the potential to be a powerful warlock. To tempt Lovecraft into using magic, Macha presents a threat: Kim will die if Lovecraft does not use magic to stop him. Hypolita eventually sends her own magic through Lovecraft to incapacitate Macha. Taking advantage of this opportunity, Lovecraft kicks the fallen Macha off a balcony into the sea, where he drowns.
Content with not being a movie star anymore, Kim stops using magic to alter her appearance and decides to leave Hollywood. Before she boards the train, Lovecraft kisses her goodbye.
