A secretive priest invites a group of academics and students led by a theoretical physicist to investigate a mysterious canister containing a swirling green liquid, which has been stored for centuries in the basement of an abandoned Los Angeles church. The group, comprised of physicists, mathematicians, theologians, and historians, is tasked with uncovering the substance's secrets. Amidst the collection of ancient texts and artifacts, they learn that the canister may be linked to an age-old malevolent force that the church has kept hidden for fear of its power.

As the team delves deeper into their research, unsettling occurrences begin to plague them. They discover that the liquid is actually a physical manifestation of Satan, who plans to emerge into the world to bring about the apocalypse. Theories turn to chilling realities when they realize that the church is a battleground between the forces of good and evil. Paranormal phenomena intensify, and the scholars realize they are not only studying the substance but also fighting to prevent an impending supernatural catastrophe.