The adventure begins in the office of the Transcontinental Railway. There is concern as the construction of the first railway line across North America is stalling. At Dead Ox Gulch, just beyond Chicago, and in Puertitas, near San Francisco. The villainous majority owner of a stagecoach company sees his fortunes slipping away due to the technological revolution and orders one act of sabotage after another. If Lucky Luke hadn't appeared on the scene to also deal with jealous mayors, unruly passengers, and upset Native Americans, the history of America might have turned out quite differently.