When DEL PIERCE was five years old, he was possessed by a demon. They called it the Hellion: a cackling wild child, a Katzenjammer Kid with a slingshot who’d shoot the glasses off your face—a stunt that cost Del’s mother her eye. With the help of pastors, psychologists, and his family, Del regained control of his body and locked the demon away inside him.

Happy Ending.

Twenty-three years later, the Hellion’s breaking out. Every night Del pops Nembutal and straps himself to the bed like Lon Chaney, but still it wreaks havoc while he sleeps. This time no amount of counseling, drugs, or meditation is going to keep the demon in its cage.

No one’s ever trapped a demon before, but Del is far from the only victim of possession. Every day since the epidemic began in the 1940’s, men and women are seized by alternate intelligences that seem to jump from person to person, roaming the network of human souls. The dozens of personalities echo heroes and villains from pulp fiction, golden age comics, and folklore, and their exploits have disrupted lives and warped history in ways large and small. “Possession” and “demon,” however, are controversial words. Where fundamentalist Christians and many other religious groups see clear evidence of spiritual warfare, neurologists see symptoms of Possession Disorder. Jungian psychologists talk about memes and archetypes. Conspiracy theorists blame the government, or aliens, or a secret race of telepaths.

With the help of his brother LEW, Del races to find someone who can help him before the Hellion takes over. His childhood psychiatrist and pastor are no help. DR. RAM, a ground-breaking neuroscientist, is killed by a demon before Del can convince him to take his case. He finally turns to MOTHER O’CONNELL, a failed exorcist from a schismatic Catholic sect. She becomes his teacher and reluctant guide. One of the first lessons of demonology, she tells him, is that the only sure way to drive out a demon is to kill the host. This is not good news.

Along the way Del faces off with demons, imposters, and fanatics. His near-death experience at the hands of a cult catapults him out of his body and into that of his brother, Lew. Del eventually returns to his own body, but now he knows the truth: he is the demon. He possessed the real Del all those years ago, and like a hostage who fell in love with his captors, assumed the boy’s life. The thing inside him that’s been trying to escape is the five-year-old boy.

This body doesn’t belong to him, but where can Del go? He doesn’t even know what he is: archetype, alien, or something stranger. With the help of Mother O’Connell, Del searches his earliest memories for clues to his origins. The trail leads to a small hospital in Kansas. There Del finds BOBBY NOON, a comatose old man who’s been dreaming the demons to life since his paralyzing accident at age 12. Noon’s fantasies are the stuff of dime novels and golden age comics, and those pulp characters formed the templates for the demons. On the night Del finds Bobby Noon, all the demons converge on the hospital; pirates fight with superheroes, cowboys rope Vikings, and monsters roam the halls. In the chaos, Bobby Noon is killed by one of his own creations, a walking expression of the death-wish called THE LITTLE ANGEL.

To his surprise, Del doesn’t die with Bobby. It seems that demons, like fictional characters and computer viruses, don’t die with their authors. And in a midnight meeting with a demon born outside of Bobby’s imagination, Del also learns that there’s more than one author in the world.

Del knows that he cannot stay­­—the boy he possessed deserves his own life. He returns home to say goodbye to Lew and his mother. Finally, there’s nothing left to do but jump. As he enters the network of souls he becomes something new in the world: more than a demon, less than a god. Guardian angel, perhaps.