In the dying days of the Wild West, Joe Baker, a roguish and charismatic bandit, dreams of carrying out one last grand heist that would earn his notorious reputation eternal fame. He plans to steal a Gatling gun, an unprecedented instrument of destruction, and use it to raid a Mexican treasure caravan. However, in order to secure the gun, he must first kidnap the wife of a corrupt military colonel as trade leverage. With limited time and mounting pressure, Baker assembles a motley crew of outlaws to execute his audacious plan, weaving through a tangled web of complications and moral dilemmas.

As the plot thickens, U.S. Army Colonel Morgan, a seasoned and principled officer, is tasked with investigating Baker's activities. Complications arise when Morgan's impending retirement and his personal code of honor confront his duty to uphold law and order. With the desert sun setting on an era of lawlessness, Morgan must navigate his way through a dangerous landscape while keeping his own moral compass intact. The intertwining destinies of Baker and Morgan set the stage for an ultimate showdown that tests the limits of ambition, loyalty, and justice in the rapidly changing American frontier.