Paradox.

Homicide detective Sean Nault is a cop on a parallel Earth whose technology is powered exclusively by magic. Sean investigates a baffling series of murders committed by a means he's never seen before: science. With the aid of Lenoir, a member of the ridiculed subculture of "pragmatists" who believe science is more than the stuff of myths & children's stories, and the 130-year-old sorcerer Winston Churchill, Sean uncovers an ominous plot that will lead him to another dimension and the realization that, unless he prevents it, both earths could well be destroyed.