Backed to the wall

the long version

"Outlaws--fueled by cruelty they became addicted to during the War Between the States--roam and prey upon anyone unfortunate enough to cross their trail. In the Dakota Territory of the 1870s, the line between outlaw and lawman is often blurred. Some of those sworn to protect the helpless might exploit them instead. And some of those deemed hard cases might redeem themselves. Backed to the Wall plunges both a lawman and an outlaw into a blood battle that only one of them can survive--if the Indian raiders terrorizing homesteaders and cattlemen don't kill them first"--Amazon.com.