Killing Spree is arguably one of the most intense novels in the series, filled with brutal non-stop action from start to finish.
Fargo has invested money in a gold mine and that investment is paying off--until four sadistic outlaws/brothers kill the prospector, kidnap his daughter and leave Fargo for dead.
However, Fargo isn't quite dead, but he is alone in a ghost town, with his weapons and his boots taken. He's tightly tied up with rawhide and beaten badly enough to leave him with broken ribs and nearly no strength.
But, then again...well, this is Fargo. Giving up isn't an option. Driven perhaps more by pure hatred than by a desire to rescue the girl, he figures out a way to get free from the rawhide.
Then, armed only with a lance made from a broomstick and a nail, carrying a few old whiskey bottles filled with water and meat taken from a coyote he beat to death with a piece of wood, Fargo sets out to kill the four brothers.
The brothers have separated, so Fargo eventually encounters each of them separately. Between these encounters, Fargo endures desert heat, pain from his injuries and--at one point--a sandstorm.
Benteen adds ambiance to the book by spending just a page or two to give the brothers enough of a history (each fathered by a different wife of an apostate Mormon) to give them some uniqueness.
He also gives each of Fargo's encounters with one of the brothers its own uniqueness, both in setting (a desert camp--a saloon--a ranchhouse--and a camp of Mexican revolutionaries) and in the weapons used.
These include that broomstick/lance Fargo initially carries, then having him move up to pistols, dynamite, and finally a machine gun and a half-dozen hand grenades.
Essentially, Fargo has access to more advanced weapons with each encounter, as well as gradually re-acquiring his personal weapons from the bad guys.
From the moment Fargo is left for dead to when he finally rescues the girl, the story never stops to breath and effortlessly carries us along with it. It may be my favorite of the series.