The Devil’s Six Gun tells the story of inventor Copernicus Blackburne. He's hired by reclusive inventor Samuel Tygean who wants a gun that will 'kill the devil, himself'. Tygean introduces the young inventor to Ghost Rock and soon the supernatural element has Blackburne's mind racing with ideas for new devices. Contained within its pages is probably the best display of the slow madness caused by Ghost Rock along with the horrible end suffered by most Mad Scientist.
Along the way Blackburne travels to Salt Lake City where we infer that Tygean wants a weapon to kill Darius Hellstromme, another major character in the Deadlands universe. To do that, he wants Blackburne to recreate his Protean Pistol using Ghost Rock derivatives. The problem is getting Blackburne to focus on weapons. Tygean discovers a method of getting Blackburne to focus but it involves robbing the scientiest of everything he loves.
The book suffers from too many words containing back story and setting information. There's a great deal of history without much in the way of dialog. I think the real issue is that the design team decided to tell the story rather than show it. The artwork is, at times, masterful producing full page illustrations of the Ghostrock-inspired discoveries of Copernicus Blackburne. That strength should have been used to more effectively show rather than tell.
If you want a glimpse at your Mad Scientist’s future, give The Devil’s Six Gun a read. The game artifact is the stats for the Gun itself. This special pistol does more and more damage with each new hit but drives the user slowly insane.