Ghosthunter: The Spectres of Saint Louis

How do you shoot a spectre?
Ghost sightings in the Saint Louis ruins. Trolls amassing across the Mississippi. A traitor hidden in the army garrison.
Beth's proven she's the best gunslinger in Golden City. Wild Bill Hickok trained her well. Now he wants her help. If anyone can figure out how to kill something that's already dead, it's her.
Time to strap on her Colt and ride.