Passé pour mort depuis 1908, Butch Cassidy, le légendaire hors-la-loi, se cache en réalité en Bolivie depuis 20 ans sous le nom de James Blackthorn. Au crépuscule de sa vie, il n’aspire plus qu’à rentrer chez lui pour rencontrer ce fils qu’il n’a jamais connu. Lorsque sur sa route il croise un jeune ingénieur qui vient de braquer la mine dans laquelle il travaillait, Butch Cassidy démarre alors sa dernière chevauchée…

Pat Garrett arrives in Abilene where he catches five of Butch Cassidy's gang. He calls in Wyatt Earp and Bat Masterson and they learn there is a half million dollar shipment of money arriving by train and Cassidy is amassing enough men to take it.

Set against the backdrop of the late 1800s, Bub Meek helplessly watches his best friend rise to infamy as an outlaw, known only as Butch Cassidy, the leader of the Wild Bunch.

Brady Sutton returns from three years in prison and tries to go straight. One a member of the Butch Cassidy gang, he is still suspected of being cahoots with them. When Cassidy and his men rob the bank, he is blamed. Escaping from the townspeople, he once again joins up with Cassidy to wait for a chance to help bring him in.

The historical account of outlaws Butch Cassidy and the Sundance Kid, whose turn of the last century exploits made headlines, led them to be pursued by Pinkerton detectives hired by the railroads, and inspired a hit 1969 film.