The Bible recounts a tale in which Jesus and his disciples came upon a pariah who was possessed. When Jesus asked the man his name, he replied that there was a legion of devils inside of him.
In Brookfield, Connecticut, 12-year-old David suffers from intense nightmares of an old man with demonic features. In his mind, the boy sees the old man flying toward his home, and his fear of impending doom grows day by day. David's mother is unsure of how to respond‚ until they see their son get physically attacked by an invisible entity.
The family contacts paranormal investigators Ed and Lorraine Warren, who make contact with a legion of demons inside the child's body. The Warrens know that, if they do not face the evil, David's soul will be consumed by darkness.