State-of-the-art medical facility Kingdom Hospital sits upon the site of a tragic mill fire and some say the spirits of those who perished haunt it. Artist Peter Rickman is left for dead after a hit-and-run accident and is frequented by visions of a young ghost named Mary and the strange beast Antubis. It is up to the talented Dr. Hook to muster all his skills to save the young man.
Dr. Stegman's complaints about Dr. Hook's repeated 'unauthorized' tests on nurse Druse's mother, Sally, are ignored by chief of staff Dr. Jesse James; Steg still throws her out as malingerer. A man is brought in, badly wounded after jumping from his roof. Hook can't make sense of Peter Rickman's contradictory paralyzed condition. Putting them on the same room starts common nightmares which cause real, apparently unprovoked damage. The circle convenes again. Sally Druse warns Hook that evil is awakening. Weird things keep happening, in hospital and in jail to multiple ...
After Dr. Hook is convinced he saw Mary, Mrs. Druse persuades him to find the child's doll. Imprisoned murder Rolf Pederson poisons himself in order to escape capture after being nursed back to health. Chief of Neurosurgery Dr. Stegman faces a harrowing battle when one of his patients is left a vegetable after surgery.
Mrs. Druse asks a dying patient to help her contact Mary's spirit. Thieving nurse Emma Warburton is frightened to death by her wily old war, Mr. Sugarly. Meanwhile, Peter and Rolf recover in their hospital room, the evil ghost Paul contacts Rolf to kill an old woman who is coming to see Peter.
A delusional homeless man with a brain tumor lands in Kingdom Hospital. Forgoing medical ethics, Dr. Stegman carelessly hones his surgical skills with a risky operation on the man. Dr. Hook takes fellow doctor Chris to see the hidden hospital buried beneath the Kingdom, where he secretly hoards valuable medical supplies and documents evidence of malpractice and negligence of his colleagues.
Paul presses Rolf to make Peter and Mrs. Druse his next victims. Dr. Stegman's malpractice suit heats up and he is forced to seek assistance of the hospital's secret medical fraternity, the Keepers of the Kingdom. Meanwhile, Mary and Peter team up to save the Antubis after Paul tries to kill him.
A philandering lawyer suffers a heart attack and winds up residing in Kingdom Hospital. After Rolf inadvertently sets himself on fire attempting to go after Peter, Natalie Rickman seeks to move the criminal to another room. Her husband has begun to communicate through drawings and when he produces eerily accurate depictions of Mary and Mrs. Druse, the psychic looks into searching for the girl's hospital records.
Attorney Sheldon Fleischer schemes to move himself up the heart donor list. Mutli-millionaire Benton Knight's organs conveniently become available for harvest with a little help from Antubis. Rolf finally gets his comeuppance after attempting to kill Fleischer, who finally gets his new heart, but only after it has been mauled by a dog.
During the New England Robins World Series bid, disgraced former first baseman Earl Candleton is inspired by Knight's suicide attempt. Reliving the mistake that cost the Robins the championship title years before, Candleton is rushed into Kingdom with a bullet in his head after the team loses again. Peter and Mary face off against the malevolent Paul for the life of the ball player, and take him back in time to erase the error of his past.
Crucified Reverend Jimmy Criss continues to perform miracles despite being dead. As the earthquakes affecting Kingdom increase, seismologist Richard Schwartzon warns Natalie to take Peter away from the hospital to protect him from the impending catastrophe. The Antubis aids the fulfillment of the resurrection prediction by bringing the prophet Criss back to life.
Officer Sol begins suffering seizures following Reverend Jimmy's resurrection, and after undergoing surgery, winds up under Paul's control. Dr. Hook continues to seek the destruction of Dr. Stegman's career, searching for an incriminating report regarding the rampant mistreatment of a patient. After killing the hospital librarian, Paul and Dr. Gottreich are able to plant documents incriminating Dr. Stegman, which then wind up in the hands of Dr. Hook's lackey, Elmer.
Natalie realizes something is happening inside Peter's brain and calls for Mrs. Druse to perform a séance, hoping it will stave off the earthquakes. Dr. Stegman is shocked to discover the incriminating reports plastered all over the hospital. Knowing this could be the end of his career he blames his cohort Brenda and learns that his misdeeds mean imminent trouble. After dismissing suicide as his way out, Stegman vows to get revenge on those out to destroy him.
Kingdom Hospital's demise draws near as the earthquakes continue to grow in size and frequency. Mary shares the hospital's tragic past with the true believers and Peter makes both her and Antubis visible. Mrs. Druse reveals that during the fire, Gottreich burned down the mill for insurance money, killing everyone inside. She enlists séance volunteers to take a sleep-inducing drug, which allows them to go back in time, seeking to change the tragic course of events at Kingdom Hospital.