... in 1873 the railroads replaced their workers with automatons, but when John Henry died in his fateful contest with a robot pile-driver, the robots learned what happens to things that become "obsolete". They promptly turned on their human masters.
With no weapons able to overcome the robot menace, the bloodshed and loss of life was too massive for the young country already reeling from the civil war. Eventually president Grant, weary of war, ceded everything west of the Mississippi to the robots.
Then in 1886, a young scientist named Nikola Tesla invented a new kind of pistol. the Tesla Electron Bolt Thrower. Armed with this new weapon the "Tesla Rangers" were formed to re-take the west.
Start to Finish Completed in 2 hours 30 min
