The Cheyennes open up hostilities by fatally wounding a lone Sioux warrior. His horse carries him to the Sioux camp, where he tells the story of the attack and expires. The Sioux go on the warpath and in a fierce battle Big Thunder is captured by the Cheyennes. His sweetheart, by tricking a Cheyenne brave, enters the Cheyenne village and cuts Big Thunder’s bonds. The lovers escape, but are hotly pursued. Brought to bay, and fighting for their lives, they are rescued by the Sioux warriors, who swoop down upon the Cheyennes and defeat them in an exciting battle.