Del's mother fought hard to free her beloved son, and in the beginning, her efforts appeared successful. Del's family recovered their good-tempered—if accident-prone—boy, and the Hellion vanished, never to be seen again. That hasn't kept Del from seeing other spiritual takeovers close up. Where it's rare for any adult to witness even one demonic possession, Del is working on his sixth as Pandemonium opens—watching as an artistically bent entity known as the Painter creates a pastoral farm scene only to depart, leaving his victim unconscious and confused.

Seeing other manifestations is the least of his worries, though: As an adult, Del has begun to question whether the Hellion ever truly left him. By day he can hear the sound of something trying to scrape its way out of his mind. By night, he is plagued by sleepwalking episodes so violent he willingly chains himself into bed, incidents that eventually put him in a mental hospital.

When Del hears of a doctor who may have isolated the part of the brain tied to possession, he enlists his elder brother in an attempt to convince the neurologist to attempt radical surgery on him. This hope is crushed when the doctor is murdered, and now, as he puts some distance between himself and a murder he's all too likely to be blamed for, Del must consider the only alternative left to him—finding an exorcist who isn't a fake.

Can brotherly love defeat a monster?

Author Daryl Gregory has painted his hero into a very tight corner in Pandemonium. The best way to get rid of a demon is to convince it to move on to another host, but Del is too nice a guy to offer the Hellion another 6-year-old. What's more, he's not even sure the demon can leave on its own. There is every indication that the Hellion may be trapped. If so, Del is more than an ordinary victim—some see him as the key to getting rid of demons and possession entirely.

In a book filled with spiritual conundrums and deranged mystics, the heart of this novel is Del's relationship with his brother Lew. The pair share a complicated, utterly believable family bond. Though they have remained friendly despite Del's various mishaps, both men clearly find themselves trapped—as adult siblings do—in roles assigned to them early in life. Lew is the responsible eldest brother, Del the chronic screwup. Their mutual devotion helps them rise above this childhood programming, and it is a pleasure to watch this unfold.

At times, Pandemonium dances up to the cliff's edge of metafiction, riffing on previous well-known SF stories. Fans of A.E. van Vogt, for example, have formed an organization around the belief that the demons are telepaths—slans—who take people over to entertain each other. Philip K. Dick appears in the novel as a character: He's been possessed by an entity known as VALIS who offers Del sage advice in times of crisis. These references to other works and authors are playful but never frivolous: They're integral to the plot and ultimately make perfect sense.

Pandemonium is inventive, quirky and darkly humorous, with a hero whose journey is far from typical, taking readers down an often creepy road to some very unexpected places.