During a brutal winter ambush that wipes out most of his platoon, command is handed to the highest-ranking survivor, Sgt. Eddie Towler, Sidney Poitier. Towler soon discovers that all the other men left standing are white, a reality that weighs on him as he weighs who should lead. He believes that ex-sergeant Sgt. Kincaid, a man with 11 years of experience, might be better suited for the job, but the dying lieutenant orders Towler to take the helm and complete a vitally important mission: to seize and hold a farmhouse perched in a mountain pass to enable the battalion’s advance. The tension within the unit intensifies when, after the lieutenant dies, Southerner Pvt. Bracken, Paul Richards, initially refuses to follow Towler’s commands, and Towler must forcibly remind him who’s in charge.
With their radio out, Towler leads ten healthy soldiers along with a gravely wounded Pvt. Casey, Richard Davalos, on a stretcher toward the objective. As they approach the farmhouse, a flash of combat triggers a grenade that wounds a Korean woman inside the home, leaving her young son and her adult daughter Maya, Ana María Lynch, to confront the danger. Some men want to pull back, but Towler insists on holding the position, and Kincaid’s presence continues to shape the debate about how to proceed.
That night, the unit repels a fierce assault. Navajo scout Hunter, Mario Alcalde, volunteers to reconnoiter in Towler’s place, and the two sides agree on a password. Hunter is captured and beaten, yet he refuses to disclose the password. After several unanswered challenges, Towler opens fire, hitting Hunter and several attacking troops. The violence ends with Hunter’s death, but he manages to utter the password before he dies.
Bracken then makes a brutal attempt to assault Maya. Towler orders him to back off, but Bracken resists, escalating the confrontation. Lazitech, manning another outpost, falls next, and Casey is carried to a gunport to fight but dies in the ensuing barrage. A flare of violence ruptures the fragile order as Towler and Kincaid clash—Towler catches Kincaid slacking off, and a brawl nearly erupts—until the distant thrum of a moving tank interrupts them.
The pair retake their focus, improvising a desperate defense with kerosene and torches to set the tank ablaze. When the tank hatch opens, Kincaid sacrifices himself by tossing a grenade inside. The vehicle runs over his leg, and Corpsman Wade, Glenn Corbett, must perform an amputation to save what remains. Only Towler has the compatible blood type for a transfusion, and the operation succeeds despite Wade’s limited training.
As the enemy columns approach, Towler summons the remaining fighters and the civilians up the pass, while he himself carries Kincaid to the outpost for a last stand. The arrival of friendly aircraft and a relentless bombardment of advancing infantry signals that the battalion is near, promising reinforcements as the beleaguered group holds on against a powerful assault.
