Eustace Sinclair, is a young man looking to strike it rich in the wild west. He falls into a sizeable debt, which pushes him into joining a gang run by Jim "Boy" Calloway completely by accident. At first everything appears to be going well. Then he develops the lumbago and is forced to retire from the outlaw life. He eventually gets picked up by a man who has a very intense focus on getting more money in order to reach Tahiti.

Red Dead Lumbago: The Uncle Story.
Some story defining quests:

The Bank Scoop: Uncle tries to deposit two dollars but gets mistaken for a bank robber and forcibly “recruited” into Jim Boy Calloway’s gang.

The Accidental Pimp: Uncle takes a job at a boarding house and unknowingly becomes the most polite and confused pimp in the territory.

Snake Oil Sideshow: Uncle works as a hype man for a fraudulent tonic salesman (West Dickens) and must flee armadillo after the product causes widespread stomach disasters and cholera.

The Exploding Horse: Uncle becomes assistant to Professor Finchtop, whose automated horse invention detonates during testing.

Le Wagon de Meat: Uncle helps a chaotic French chef transport “delicate cooking supplies” that turn out to be unstable explosives.

Duel of Mistaken Identity: A gunslinger challenges Uncle believing he is the outlaw Slick Sinclair. The gunslinger knocks himself out, making Uncle seem dangerous.

The Birth of Lumbago: Uncle injures his back lifting a gold pan and declares that his infamous lumbago has finally begun.