Tissue-thin and Mexico-centric revenge plotline about Slocum getting back at the murderers of an old buddy (like Captain Kirk's girlfriends, it's hate to find a job with less of a life expectancy than 'old buddy of Slocum'). Somewhat unconvincingly, the gang of rustlers responsible consists of a bandito, a peasant who is also a bandito, the foreman at a prosperous ranch, and a generalissimo type (Central Casting did not have to reach deep into the Rolodex for any of these guys).
It boils down to a series of vignettes in which Slocum does typical pulp heroism stuff like going undercover, resisting torture, camouflaging himself with river clay. Pretty much the usu. The only real sex scene involves butt stuff, which does come as a surprise--what's next, feet? Traps? But this is an Adult Western where the Adult is largely an afterthought.
The author has an annoying tendency to egregiously put his thumb on the scale for Slocum. In one scene, he's poisoned by peyote before an assassination, but then the assassins are taken out by Indians who conveniently leave the hallucinating Slocum alone. Later on, Slocum survives playing cat and mouse with an armed villain when another villain suddenly betrays the first for hitherfore unrevealed slights and then wanders off, leaving Slocum free to resume the plot. This sort of thing might be forgivable in some romantasy that's just smut with a few magic spells thrown in, but in a book that's 99% Western, you're pretty obligated to make the 99% good Western, aren't you?