Richard Clarke's "The Arrowhead Cattle Company"
When Fred Oakley buried his son and daughter - in - law, the last thing he did was to tuck in his young grandsons Jaime and Arthur Oakley and by next morning was simply gone!
The two bewildered youngsters struggle manfully to survive all alone, their lives constantly under threat by the homicidal neighbor rancher, Steve Hearst.
First he steals their cattle then his hired killers shoot at them.
After six months or so an all but penniless stranger rides up with a deed to their property signed off by their wretched granddad who lost it a poker game -- 500 miles away.
This Man on a Horse, the beautiful widower sheriff's eligible sister, Elizabeth, along with Doc Pettinger and a sympathetic saloon owner named Benour -- who knows first hand the tragedy of being an abandoned and exploited orphan -- form a sort of conspiracy of hearts, to do the right thing!
And that's when Hearst and his killers really turn violent!
A good read! :)