The Lonesome Cowboy is forced to hang up his spurs by an ambitious lawman from Chicago. It's the start of the 1860s, and the Old West is changing-a change that comes as a shock to the Daltons when they're arrested not by Lucky Luke, but by - Allan Pinkerton! The man is determined to turn bandit-hunting into a modern, rational business-even at the cost of the American people's personal freedom. It'll be up to Lucky Luke to ensure that the USA is protected against all evil-doers, rascals and lawmen alike -