In an alternate 1948 Los Angeles where magic and myth simmer in the shadows of the city, detective Phil Lovecraft refuses to use any form of magic, choosing a grounded, rational path to crime. When wealthy widower Amos Hackshaw, David Warner, offers him a dangerous job—locate the Necronomicon, a powerful grimoire that Hackshaw both stole and which had been stolen from him—Lovecraft accepts the case, drawn by the challenge rather than power. Hackshaw’s cosseted teenage daughter, Olivia Hackshaw, Alexandra Powers, spends her days chasing unicorns, a pastime tied to mystic lore that says unicorns can only be approached by female virgins. Hackshaw chooses Lovecraft precisely because Phil is notorious for refusing to wield magic, believing that a man of his resolve can outmaneuver the book’s dark temptations.
The investigation sweeps Lovecraft into a tangled web of old loyalties and fresh betrayals. At the Dunwich Nightclub, he runs into Connie Stone, Julianne Moore, a former girlfriend who now performs as a singer. He also confronts Harry Bordon, Clancy Brown a former LAPD partner turned brutal mobster who has his own designs on the grimoire. Bordon has already had Mickey Locksteader, Ken Thorley, killed after Locksteader sold him the Necronomicon; a double-crossing misstep leaves Bordon with a counterfeit book—one made of blank pages that looks convincing only to a fool. The morning after, Lovecraft shares breakfast with Olivia when a demon is magically summoned to attack him, forcing a frantic escape. After a brief interrogation by the police, he tracks down Lilly Willis—also known as Larry Willis, Locksteader’s transgender ex-lover and Hackshaw’s former chauffeur—who is deeply entangled in the Necronomicon’s sudden shifts in hands. An animated gargoyle, Michael Reid Mackay, bursts in and slays Willis/Lilly, and Lovecraft and Connie flee with the grimoire, only to be betrayed by Connie to Bordon.
As the pieces fall into place, Bordon, Connie, and Hackshaw reveal a fearsome plan: to use the grimoire to summon one of the Old Ones and seize godlike power. The ritual demands a virgin for the offering, and Olivia becomes the focal point of this dark ritual, her life poised between salvation and doom. In a shocking turn, Connie shoots and kills Bordon, but Hackshaw’s zombie bodyguard closes in, crushing Connie’s gun hand and ending her immediate obstruction. Hackshaw then outwardly seems to seal his own fate as he summons the Old One; the creature appears, but instead of granting power, it devours Hackshaw and vanishes back into the earth. The ritual fails because Olivia had already lost her virginity a few days earlier to the police detective assigned to guard her, undoing the ritual’s intended purity.
In the wake of the carnage, Connie and Lovecraft share a hesitant kiss, a brief moment of human connection amid the surrounding chaos, before she is arrested for murdering Bordon. Lovecraft exits with the Necronomicon, convinced that the mythic artifact has effectively been destroyed and that its dark powers won’t be unleashed again—at least, not by him. The city’s strange chemistry lingers around him: magic remains a hidden presence in an otherwise gritty noir landscape, and the fate of the Necronomicon hangs in unresolved question, leaving room for doubt, danger, and the possibility that some legends refuse to stay dormant.
