Autumn 1864 finds the remnants of the Confederate 5th Georgia Cavalry as prisoners of war in the Union prison camp at Rock Island, Illinois. The men are racked by illness and kept in dire, unsanitary conditions, yet a glimmer of survival appears when Union Captain Mark Bradford, Cornel Wilde, offers them release from what one prisoner calls a “this stinking pesthole” if they will join the Union Army to garrison a frontier fort. The outpost is Fort Thorn, in the harsh reaches of New Mexico, a small, understrength post where the regulars have been sent east, leaving only greenhorns or casualties to face the dangers beyond. The harsh choice is to serve a cause they once fought against, and the decision to accept is settled by a tie-breaking vote that is broken when Col. Clay Tucker, Joseph Cotten, much to his own reluctance, agrees to the terms to save his men.
The Georgians’ transfer to Fort Thorn brings them into the crossfire of old loyalties and new dangers. Major Henry Kenniston, Jeff Chandler, commands the fort with a stern, wounded gait—a limp that marks him as someone who has seen too much. He treats Tucker with a mix of command and condescension, and the social tension is sharpened by Tucker’s dining with Kenniston, his widowed sister-in-law Elena Kenniston, and other civilian guests. Elena, Linda Darnell, is wary of Kenniston’s protective attitude, sensing that he sees himself as a surrogate for her late husband’s memory. Tucker, who once led the cavalry charge that killed Elena’s husband, feels the weight of that past as the two factions spar over discipline, pride, and duty.
The atmosphere at Fort Thorniss is strained from the start. Northern and Southern soldiers clash in temperament and tactics, and when Tucker’s unit attempts to pursue a band of Indians, they are ordered to halt, and Kenniston warns them that they may be walking into an ambush. Tucker challenges the orders, and the tension deepens as the fort assigns two civilians convicted of gunrunning—actually Confederate agents—for punishment. Tucker objects to what he regards as a violation of their enlistment but finds himself outmaneuvered. As events unfold, Ephraim Strong, a civilian who conceals his Confederate allegiance, Harry von Zell engineers a plan to link California to the South and, more importantly, to keep Tucker from deserting. He nudges Tucker toward a dangerous compromise: instead of deserting, Tucker should escort a wagon train through hostile terrain and then return to Fort Thorn with Elena, thereby winning Kenniston’s trust. Elena’s daring escape in a concealed wagon adds another layer of suspense to the plot, though Tucker ultimately agrees to the risky arrangement.
The situation becomes even more perilous when Kenniston orders Tucker to carry out a controversial act: the execution of a Kiowa warrior, the son of chief Satank, whom Kenniston brands a “rebel and traitor.” Tucker is then ordered to join the Confederates and Bradford is taken prisoner. He is escorted back to the fort, only to return with alarming news—the fort is under siege by hundreds of Kiowa warriors. Despite serious misgivings, Tucker resolves to move back to Fort Thorn and fight alongside Bradford’s men to hold the line until nightfall can bring relief. The standoff tests every nerve as they struggle to defend the garrison against overwhelming odds, and Bradford is killed during the fighting.
In the aftermath, Kenniston makes a final, sacrificial gesture by stepping aside and handing command to Tucker, recognizing that the fort’s survival now depends on Tucker’s leadership. A dispatch rider brings the long-awaited news that Gen. Sherman has completed his march to the sea, a signal that the Confederacy’s cause has become untenable. The victory is tempered by loss and fatigue, but Elena offers a quiet, human counterpoint to the devastation: she comforts Tucker and holds out the hope that tomorrow may bring better days.
Throughout, the atmosphere is dense with moral ambiguity, loyalty, and courage. Tucker’s arc—from reluctant sacrificer to a commander trusted to guide his men under fire—forms the emotional core of the story, while Kenniston’s stubborn rigidity and Elena’s quiet resilience illuminate the personal costs of war. The fort, the frontier, and the fractured loyalties of soldiers on opposite sides of a divided nation become a crucible in which endurance is tested, and where the human spirit sometimes finds a way to endure beyond the immediate battles.
> "this stinking pesthole"
> "greenhorns or casualties"
