The Last Warriors

In 1877, one year after the Sioux and Cheyenne defeated General George Custer at the Battle of the Little Bighorn, Talking Elk, a prominent war chief, rides in with Crazy Horse to surrender at Fort Robinson but turns back before getting there.  He can't live as the U. S. Government demands and turns, instead, to driving the gold miners out of the Black Hills who are there illegally.  The Black Hills, Paha Sapa, sacred land to the Sioux, was promised to them in the Fort Laramie Treaty of 1868.
Other warriors join Talking Elk to form a war party.  Together, they raid the miners' operations, bringing in soldiers to protect the miners.  Lt. Benson and his men are sent out from Fort Robinson to capture the renegades, but they find Deadwood, a burgeoning mining camp, and decide to station themselves there as saloons and brothels are plentiful.  And besides, Lt. Benson believes, he and his men will be safe in Deadwood from the Sioux war parties.
Talking Elk's war party is small, but they successfully defeat the other soldiers sent from Fort Robinson by the Commander, Colonel Harris.  Because of this, Sgt. Brad Jackson and his men are sent from Fort Yates, but Brad Jackson is an outlaw and quickly realizes he and his men can kill the miners, take their gold, and desert the Army to live a better life elsewhere, all to the blame of the Sioux.
When word of the renegade Sioux reaches General Sherman in Washington, he orders Major Cummings from Fort Abraham Lincoln to hunt down and kill the Sioux before things get out of hand.  If these renegades are allowed to live and raid miners more Sioux warriors will follow, causing an insurrection against the United States Government. Major Cummings is a serious soldier who sees a promotion and reassignment to a plush job in Washington with the successful completion of this mission.
 For merely killing a few renegade Sioux who are standing up to the government's illegal taking of their land, Major Cummings sees that he can retire handsomely to be admired by Washington's elite for helping fulfill the promise of Manifest Destiny.  And, besides all that, Major Cummings believes his wife deserves a better life than the one provided for her at Fort Abraham Lincoln.