David Norliss, a writer who investigates the occult to expose frauds, vanishes from his San Francisco home, leaving behind a stack of audio tapes that detail his latest inquiries. The story unfolds through the perspective of his friend and publisher, Sanford Evans, who listens to the tapes and pieces together Norliss’s recent discoveries.
David Norliss had been looking into a case raised by Ellen Sterns Cort, a widow who claims that her recently deceased artist husband, James Raymond Cort, was attacked one night on their estate near Monterey. Ellen explains that James, already weakened by a crippling illness, became entangled with the occult after meeting a mysterious woman, Mme. Jeckiel who attended one of his exhibitions. She also mentions a scarab ring Jeckiel gave James, a ring that she believes holds the key to troubling events surrounding James’s death.
In Carmel, a young woman named Sarah Dobkins is found dead after a violent car crash, her skin described as a dark grey and blood seemingly drained from her body. Norliss travels to the coastal town to speak with Sheriff Tom Hartley and to press Ellen for more details. Together, they explore James’s crypt on the Cort estate, where Norliss discovers the ring still on James’s hand. He then travels to San Francisco to meet Charles Langdon, a gallery owner who had phoned Ellen about acquiring James’s ring. Langdon, upon hearing that the ring was buried with James, tries to seize it, but discovers the coffin empty and encounters a supernatural threat in the process, as the reanimated James attacks him.
Norliss’s path crosses with Jeckiel, who warns him to stay away from the Cort property. That night, Ellen and Norliss search James’s art studio and find a towering sculpture that, according to Ellen, did not exist days earlier. The ghastly James interrupts them again, and Norliss fires at him multiple times. This confrontation spills outside as James rips the car door off their vehicle. When Sheriff Hartley joins the pursuit, they find James’s crypt emptied once more.
Ellen Sterns Cort is joined by Marsha Sterns, Ellen’s sister, who arrives at the estate hoping for a quiet stay but finds the house deserted. James, however, breaches a motel where Marsha has sought refuge and drags her into the surrounding woods.
Norliss’s research uncovers a network of tunnels dug beneath the Cort estate during the 1920s. Laboratory analysis of clay from the sculpture reveals traces of human blood, suggesting a ritual purpose behind the artwork. Jeckiel returns with a urgent warning: James forged a pact with the Egyptian deity Sargoth in exchange for immortality, and the only way to stop him is to remove the scarab ring.
The pair venture into the tunnel system, where they find James resting in a pine coffin. Jeckiel attempts to extract the ring, but James awakens and pursues them. Ellen’s path leads them to a revelation: Langdon’s and Marsha’s corpses lie nearby, and the chase culminates in James’s art studio. There, James completes a dark ritual to summon [Sargoth], bringing the living statue to life. Norliss manages to thwart the ritual by fulfilling Jeckiel’s instructions: he burns the studio to ash, destroying the summoned entity and ending James’s control over the rite.
As the smoke clears, Evans finishes listening to the tape and begins to wonder whether Norliss’s disappearance is connected to the evidence he has just heard. He starts another tape that documents a second event, leaving the mystery unresolved and hinting at further revelations yet to come.
