Penniless Irish immigrant Michael Devlin arrives in New York City, USA, in 1864, the third year of the American Civil War. With a group of friends from his home in County Galway, he enlists in a cavalry regiment. After basic training, they are thrown into the Union Civil War against the Confederate South. On a reconnaissance mission, Michael discovers he is unable to fire on Confederate soldiers. To avoid the taking of human life, he volunteers for duty with a special unit of cavalry in Denver, Colorado. Michael's mission in the Mounted Cavalry in Fort Weld, Denver, Colorado, was to escort a tribe of Cheyenne Indians from a traditional Indian village to a new reservation one hundred miles away. Among the Indian nations, a reservation was a euphemism for a prisoner of war camp. It was the depth of winter; harsh inclement weather would claim many Indian lives. Beaten and whipped, the weakened Cheyenne tribe could travel no further on the forced march. Michael witnessed US soldiers sadistically slaughter defenseless braves, women and children. The killings had a profound effect on Michael and change the course of his life. On learning of a secret government conspiracy to exterminate American Indians by means of genocide, Michael becomes a leader of the persecuted Cheyenne tribe. He initiates several triumphant and bloody skirmishes against the murderous US Cavalry soldiers. He leads the remainder of the Cheyenne tribe to eventual freedom after a long exodus to Mexico.