After welding the thumb of a nearly dead car crash victim onto the lonely stump on his hand, our morally ambiguous London mage finds his new appendage has a life of its own. Following where the stranger's restless thumb takes him, John Constantine hears a name he'd rather not. Meanwhile, Constantine's young bride, Epiphany, grapples with an old addiction and a bizarre former tutor, while John's damaged niece Gemma continues her quest for vengeance . . .