A team of phony, scam-artist mediums bilk money out of unsuspecting clients until, much to their surprise, some real ghosts arrive to haunt them.

In an abandoned house in Willows Lake, the deceased Criswell awakens in his casket and offers to relate a story of a world between the living and the dead: During a routine evening at an east Los Angeles police station, desk officer Sgt. Crandel attends to numerous situations including a report by an elderly couple. Later, Capt. Robbins summons Lt. Dan Bradford and reminds him of the recent unsolved murder of a young teenage couple near the Willows Lake house. The press blamed the murders on a disturbed killer, but Robbins then details the account by the elderly couple, Martha and Henry: While driving to see Henry's infirm sister, the old couple lose their way in a rainstorm until Martha recognizes the Willows Lake house. She recalls that a mad doctor who made monsters owned the house, but Henry reminds her they were all killed when the house was struck by lightning. Their car stalls in front of the house just as a strange woman dressed in white steps off the front porch. Martha screams in terror, prompting the figure in white to retreat. After restarting the car, the frightened couple drive to the police station to report their strange sighting. In the present, Robbins orders Bradford to make an immediate investigation of the house, which although repaired since the lightning strike, has remained unoccupied. Bradford arrives at Willows Lake, unaware that he is observed from the woods by a dark-haired woman dressed entirely in black who is responsible for the teenagers' deaths. Bradford finds the front door to the house unlocked and upon entering is met by a man in a turban who introduces himself as clairvoyant Dr. Acula. Pretending to be interested in a spiritual reading, Bradford accompanies Acula through the darkened house to a curtained room where an older woman, Mrs. Wingate Yates Foster, and her younger male companion sit at a long table facing several prop skeletons. Another man, Mr. Darmoor, asks when he might speak with his dead wife, and Acula assures him that he will have the opportunity very soon. Outside, the woman in white walks near the house, but shrieks upon seeing the woman in black in the woods. Meanwhile, at Robbins' request, patrolman Kelton arrives at Willows Lake and nervously examines Bradford's empty car under the watchful gaze of the woman in black. Upon hearing strange sounds and glimpsing the woman in white, Kelton fearfully fires several shots, then radios headquarters to call for assistance. Inside the house, Acula conducts a séance, summoning the spirit of Mrs. Yates Foster's dead husband from whom she seeks approval to remarry. Bradford watches the ceremony dubiously, astounded that the participants are taken in by Acula's routine. After the ceremony, Acula's assistant Tony speaks to him and Bradford uses the opportunity to slip away to explore the house. In his dressing room, Acula meets the woman in white, who is his other assistant, Sheila, whose job is to frighten off unwanted visitors to Willows Lake. Sheila anxiously relates seeing the mysterious woman in black, but Acula assures her that real ghosts do not exist. Upon realizing Bradford has disappeared, Acula orders Tony to have Lobo, the scarred, mute, solitary survivor from the mad doctor's experiments, to find him and take him prisoner. Searching the house's upper floors, Bradford discovers Acula's props and lighting devices used in the phony séances. Bradford then comes upon what appears to be a mannequin resembling the woman in black and is startled when the figures moves and beckons to him. Fleeing into the hall, Bradford is captured by Lobo and Acula, who discovers Bradford's police identification and gun. Outside, Kelton finally overcomes his fear and sets off for the house to find Bradford. Seeing Kelton approach, Acula orders Lobo to lock Bradford into a room, then dispose of Kelton while he and Sheila conduct the next spiritual reading for Darmoor. In the midst of the ceremony, Kelton bursts in and places the group under arrest only to be attacked by Lobo. Although Kelton fires several shots that strike Lobo, the oversized mutant knocks the policeman out and drags him away. Bradford manages to break out of his room and, evading Lobo, finds a room with a casket holding Kelton. Back in the séance room, Acula calls off the rest of the ceremony, apologizing for the strange disturbances. Desperate, Darmoor pleads with Acula to continue the next night and, as a token of good faith, leaves a check for ten thousand dollars. After Damoor departs, Acula tells Sheila that the money will allow them to flee before the police can investigate them. Meanwhile, Bradford revives Kelton and the men search for Acula, unaware that Robbins and another policeman have arrived in answer to Kelton's summons. Bradford and Kelton enter the séance room and as the bleeding Lobo attacks them, Robbins and the patrolman arrive and kill Lobo. Tony informs Acula and Sheila about the arrival of the additional police and goes to stall them while Acula prepares to escape. The clairvoyant and Sheila enter a room where they are confronted by numerous figures that are the revived bodies of all the people Acula has killed while carrying out his fraudulent scheme. Criswell is among the dead and informs Acula that he is to join those he has tormented. After Sheila escapes, the dead men fall upon Acula, then place him in a casket that they carry away. Sheila flees outdoors where she is confronted by the woman in black, whose powerful gaze lures Sheila to join her into the mist. After fighting off Tony, Bradford, Robbins and the others find Acula lying dead in a coffin, surrounded by numerous skeletons. Unable to locate Sheila, the men are left to wonder about the strange happenings.