The time is The Thirty Years War, and the whole of Europe is in devastation, Graf Ulrich von Bek, killer, survivor and mercenary captain of fearful repute, deserts his soldiers after an outbreak of plague and finds himself travelling through a dense forest, at the heart of which there stands an empty but unplundered castle. He takes refuge there.

But this is no shelter, for the lord of the castle is Satan himself. Von Bek has been granted entrance so that the Devil may offer him a most unusual bargain. Lucifer will relinquish his claim on von Bek's lost soul, but the price is success in a quest that Lucifer himself cannot undertake. The Devil wishes to be reconciled with God, and to prove his sincerity to Heaven needs the Cure for the World's Pain.

But even among the damned there are those who fear change. And even as von Bek accepts his quest, Hell raises in rebellion to stop him.