When Wes Montana's Arapaho mother is murdered‚ the hired gun discovers his white father Ray Eastman‚ who had abandoned them before Wes was born‚ is still alive‚ wealthy with family‚ and may have ordered her death. Swearing vengeance on his own father‚ Wes yet finds himself on his father's side in the middle of a range war fueled by Eastman's unfaithful wife. Wes likes his half-brother but is afraid of Rosalie‚ a beautiful Irish orphan‚ even as the war explodes in a fight to survive against all odds before the truth is known. Shadow on the Mesa follows the fight for survival as bad men outnumber the good‚ and Wes Montana's thirst for vengeance against his own father takes an unexpected turn.