As a child growing up in 1930s New York, Jamsie Z. is followed around by a vision he calls Uncle Ponto. A shrill, foulmouthed, and viciously cynical imp with blood-red eyes, Ponto is Jamsie's companion in rage against his criminal parents. When Jamsie becomes a radio broadcaster, Ponto is there to dictate fast-paced, edgy monologues that are a hit with listeners and guarantee Jamsie commercial success.

The story of Jamsie Z. and Uncle Ponto, described in Malachi Martin's Hostage to the Devil: The Possession and Exorcism of Five Living Americans (1976), starts off happily but grows gradually darker over time. As Jamsie begins to gain self-confidence and recognize his autonomy, Ponto goes on the attack, driving Jamsie's coworkers away, wrecking his social life, and tormenting him night and day with endless obscene rants, criticism, and-when all of that is not enough to break Jamsie's will-horrific visions. After considering suicide...