Synopsis for
Renegade (2004) More at IMDbPro »Blueberry (original title)

In the US, the film was released on DVD in November 2004 under the title Renegade and marketed very much as a conventional Western.

It is not a conventional Western at all. In addition to the plots mentioned above about the gold, there is an additional plot, which arguably, is actually more what the move is truly about, with the 'gold hunting' being more of a 'backdrop' plot, in my opinion.

U.S Marshal Mike Donovan (referred to as Broken Nose by the native tribe; unlike in the comic he does not have the nickname Blueberry) has dark memories of the death of his first love. He keeps peace between the Americans and the natives who had temporarily adopted and took care of him. The evil actions of Blount, a "white sorcerer" lead him to confront the villain in the Sacred Mountains, and, through shamanic rituals involving native entheogens, conquer his fears and uncover a suppressed memory he would much rather deny.

That last paragraph, is taken verbatim from Wikipedia. As far as I can tell, there shouldn't be any problem with that. I just wanted to give credit to the original author, as I never could have hoped to describe it so well -- but I wanted to put this here, so that others looking into this movie, will know, it's not 'your average western', as it was marketed as in the US.