From the back of the adventure:
"That Old Time Religion...
Something lurking in the wasteland outside of Salt Lake City has been holding up Professor McClellan's horseless and driverless stagecoach-and apparently the bandits are only interested in stealing one thing: human hearts!
When Ronan Lynch hires on to investigate the gruesome killings, he gets a lot more than he bargained for, in the form of an ancient Spanish galleon in the dead center of the salt flats! It's up to Ronan to figure out how the shop got there, miles from any ocean, and how it's connected to the murders. When he does, the gunsliner finds himself fighting for his life against the Forbidden God himself!"