Biopunk

There have long been ghost stories and strange accounts of a presence in The Great Woods, a series of forested areas that carve out from the Wyoming Territory and spread across the northwest clear to the Pacific Ocean, but these were discounted as superstition and Native mythology. Settlers who never came back were assumed to have settled peacefully or died en route to their new lives. It wasn't until the city of Cheyenne was built by the Union Pacific Railroad, and the first tree was carved into for the purposes of laying tracks further west, that these rumors were substantiated. In one brief backlash, representatives of the railroad and their Union Army backers were expelled from the city by a small force of rebels from the woods using strange and advanced arboreal technology. Cheyenne became a ghost town overnight and the forest quickly began to take hold of the now abandoned buildings and tracks, claiming them for its own.

In the prairies to the East the Union Army licks its wounds and contemplates what to do next. Rumors circulate about bizarre experiments on samples claimed during its defeat to try and harness the botanical prowess of the woods. The Union Pacific Railroad sends negotiators into the dead city to see if a peaceful resolution can be reached, while men and women from the woods emerge to explore and investigate the ruins. Suddenly scientists, soldiers, and the curious begin to arrive from both sides, creating an unstable ceasefire at ground zero.

This is Cheyenne, Wyoming, 1868, the strangest city in the world. The slightest misstep can claim your life, your mind, or even your soul.