The Texan Confederate army under General Henry H. Sibley, their supply train destroyed by the 1st Colorado Union Volunteers at Glorieta Pass, have only one prize remaining: a battery of Union artillery captured at the Battle of Valverde. The Texans, their force decimated, dispirited by the absence of fallen comrades, are determined to have some glory to show for their terrible losses. But standing in their way are Union Captain Alastar O'Brien and the Colorado Volunteers.