During the Civil War, a group of Confederates escapes from the Union POW camp at Fort Bravo but has to contend with the desert, the Mescalero Apaches and the pursuing Union troops.
Lieutenant John Dunbar, assigned to a remote western Civil War outpost, finds himself engaging with a neighbouring Sioux settlement, causing him to question his own purpose.
In 1864, due to frequent Apache raids from Mexico into the U.S., a Union officer decides to illegally cross the border and destroy the Apache, using a mixed army of Union troops, Confederate POWs, civilian mercenaries, and scouts.
A Confederate Major and his troops are falsely led to believe the Civil War is not over, and become wanted men after they attack a Union Army wagon train in Nevada.