Francis Simnel was a pathetic old man who lived in a strange world of his own, a world of puppets and marionettes. His sister Agnes was a demoness incarnate, a female fiend in human form, a relentless, ruthless, driving force urging the old man to a macabre destiny. There was something different about Simnel's Puppets. They had personality and a realism that was uncanny. They bore a sinister resemblance to the newly-dead.
What began as the wildest and most improbable suspicion, crystallised into near certainty in the mind of Josephine Starr. She began asking questions, and the Satanists scented danger. She fell into a trap that had been set with diabolical cunning. Her life was balanced on a razor edge, with all the macabre resources of the Black Magicians weighing against her.