While investigating a country priest's murder, Jules is lured to a secret base of the League of Darkness, where they are creating a flying ship called the Prometheus. Jules accepts a commission at the behest of the ship's beautiful commander, unaware of the League's true purpose.

The crew of the Aurora decide to go on a tour of the United States. They meet up with a young boy, Al, who they find is mechanically inclined and partially deaf. They also discover he is an incredible mechanical genius, having recreated the design of the Cardinal's Chariot (from The Cardinal's Design).