The great state of Texas is a land of opportunity. For outlaws. And horse thieves. And cattle rustlers. Not to mention bank robbers, train robbers, and anything-that-ain’t-nailed-down robbers. The state’s governor, Richard B. Hubbard, is at the end of his rope. He wants to clean up Texas once and for all - and he’s desperate enough to try something crazy: hire a man who can do what the Texas Rangers can’t. A man not tied down by a wife or children. Or rules. Who’s not afraid to go outside the law. Who will protect the good people of Texas at any cost.

They say you can’t teach an old dog new tricks. But old cowboys? That’s a different story—especially when those cowboys are trail-hardened cattlemen like Casey Tubbs and Levi Doolin. When these longtime buddies learn that their bosses are getting out of the beef business, they figure it’s probably time to retire anyway. Nothing left to do now but deliver the last two-thousand cows to Albilene and collect their pay. There’s just one problem. Their bosses’ lawyer is skipping town with all the workers’ cash—which means Tubbs and Doolin have one last job to do...

It’s 1852. The wounds of the Mexican War are healing. Regis Royle, co-owner of a steamship fleet, has made it out alive, relatively unscarred and with enough profit and foolhardy ambition to envision a new life in south Texas. With the help of his crack-shot kid brother Shepley, his glad-handing riverboat partner Cormac Delany, and his old friend, raw-edged former Texas Ranger Jarvis “Bone” McGraw, Regis is laying claim to the prime jewel in a magnificent rolling prairie: the Santa Calina range teeming with wild mustangs, cattle, and eighteen-thousand acres of lush promise.

In his younger days, Taylor Callahan didn’t know right from wrong—and didn’t much care either. As a Confederate bushwhacker, renegade outlaw, and all-around hellraiser, he gave the devil himself a run for his money. Somewhere along the road to perdition, he decided to change his wicked ways. To atone for his sins. So he became a traveling preacher. But Taylor Callahan is no ordinary preacher. He rides the Western circuit looking to help lost souls. His mission of peace takes a violent turn when he enters the godforsaken town of Falstaff, Texas.

With Apaches on the prod, ex-cavalry sergeant Sean Keegan, bounty hunter Jed Breen, and ex-Texas Ranger Matt McCulloch take shelter in a West Texas way station - along with a hot-as-a-pistol female bound for the gallows, a spiteful newspaper editor, and a coward with $50,000 who promises them five grand if they'll deliver his blood-soaked stash to his wife. Turns out, Indians might be the least of the problems for the trio, soon to be known as the Jackals. The loot's stolen property of the vengeful Hawkin gang, and these prairie rats are merciless, stone-cold killers.