Phyllis Coates, TV's erstwhile Lois Lane, essays one of her largest film roles in Blood Arrow. Coates is cast as a devout Mormon girl whose mission is to transport smallpox vaccine to her friends and neighbors. Unfortunately, this requires her to journey through hostile Indian territory. Appointing themselves as the girl's unofficial protectors are Indian scout Scott Brady, trapper Don Haggerty and (reluctantly) gambler Paul Richards.

"Only a fool sticks his neck out for somebody else. Don't get in the habit of it." Outlaw gunslinger Sam Garrett offers that sage wisdom to fellow fugitive Tom Cameron, who's on the run from the "Bluebellies," Texas State Police officers who wield a brutal iron fist of enforcement in the early 1870s. But quick-draw, hard-bitten Garrett soon decides not to take his own advice after young Cameron heads home to surrender - and instead gets framed for a revenge murder by a jealous rival for the affections of his girl.

Wes Anderson is caught cattle rustling and promptly jailed. The public is outraged, but, since Wes always worked at night, they don't know what he looks like. Still, they break into the prison and lynch a hobo they think is Wes, while the actual culprit sneaks off to see his old flame, Rela, who has recently taken up with his straitlaced brother, Tom (William Ching). But Tom is envious of his outlaw brother, and he decides to join Wes in a life of crime.

A young woman discovers she is the daughter of the infamous Dr. Jekyll, and begins to believe that she may also have a split personality, one of whom is a ruthless killer.