The film centers around Maya Larkin (played by Winona Ryder), a young woman who works as a writer and researcher specializing in religious phenomena. Maya becomes convinced that a man named Peter Kelson (played by Ben Chaplin), a bestselling author and self-proclaimed atheist, is actually a demon incarnate.
Maya’s suspicions are aroused when she attends one of Peter’s lectures and witnesses him reciting passages from a book written in Aramaic, a language he claims not to understand. She becomes convinced that Peter is possessed by a demon and is planning to unleash evil upon the world.
Determined to stop Peter, Maya enlists the help of Father Lareaux (played by John Hurt), a Vatican priest who specializes in exorcisms. Together, they uncover evidence that suggests Peter is indeed a demon who has inhabited various human bodies throughout history.
As Maya and Father Lareaux race against time to stop Peter, they encounter numerous obstacles and supernatural phenomena. They discover that Peter is planning to perform a ritual that will allow him to open a portal to hell and unleash demonic forces upon the world.
In a dramatic climax, Maya confronts Peter as he prepares to complete the ritual. With the help of Father Lareaux, she engages in a spiritual battle with Peter, attempting to exorcise the demon from his body and prevent the apocalypse.
As the ritual reaches its climax, Maya and Father Lareaux succeed in banishing the demon from Peter’s body, saving him from damnation and preventing the apocalypse. However, in the process, Father Lareaux sacrifices himself to ensure that the demon is defeated once and for all.
In the aftermath of the battle, Maya reflects on the experience and the dangers of denying the existence of evil. She realizes that she must continue her work to combat demonic forces and protect humanity from the forces of darkness.
“Lost Souls” is a chilling and suspenseful thriller that explores themes of faith, redemption, and the battle between good and evil. With its atmospheric cinematography, eerie soundtrack, and intense performances, the film offers a gripping journey into the supernatural world and the human soul’s capacity for both darkness and light.