Evil may soon consume mankind, if the demons have their way.

After the death of her father, young Cyndi Fisher travels to Paris to meet the grandfather she never knew. That man turns out to be Father Jack Cahill, a renegade exorcist who was unaware he'd fathered a child before taking his vows.

Cyndi is soon drawn into Father Jack's world, where demons from Hell are possessing humans and robbing Europe's churches of sacred relics. From the cathedrals of Paris, through the graveyards of France, and into the sewers of Rome, they confront the possessed, battle risen corpses, and fight gang members sent to stop them.

They uncover a plot to set Satan free upon the Earth, but stopping it seems impossible. Demons are always one step ahead of them, and each manifestation is more powerful than the last. Stopping Satan's return will take courage and faith. Will an aged priest and an agnostic teen have enough of either?