Americans take a vital hill in Korea but have trouble holding it.

In 1953 at Panmunjom, Korea, a conference between American and Communist forces convenes to discuss halting their three-year conflict. Meanwhile an area in the neutral zone, dubbed Pork Chop Hill by the Americans, is retaken by the Chinese at the cost of the entire American infantry company. Soon after, "K" Company commander Lt. Joe Clemons meets with division commander Col. Davis to receive orders to retake the area and is assured that "L" Company will protect Clemons' flank. Knowing that Pork Chop Hill holds no strategic value, Clemons surmises to friend and co-commander Lt. Suki Ohashi that the action will underscore the Americans' strength while the peace negotiations continue. Clemons divides the company into three platoons, leading the first, placing Ohashi in command of the second and holding the third in reserve. As the two platoons ascend the hill at dusk, American artillery bombards the crest but the men are nevertheless unnerved to hear a Chinese broadcaster in the central command bunker calmly call out criticism of their foolhardiness and list statistics of American losses. Unknown to Clemons, back at division headquarters, Davis learns that "L" Company has been delayed getting into position because they have misconstrued their orders to provide support for Clemons' company. Once the American shelling stops, Clemons' men fall under an increasingly heavy enemy barrage and the soldiers are then shocked when bright spotlights from their own position abruptly shine down upon them, escalating enemy fire. The lights go off, and moments later, the radio man informs Clemons they have received an apology from the American group responsible for the spotlights who mistook their location for another. At dawn, still some distance from the trenches and with his platoon severely depleted, Clemons is unable to rouse Ohashi on the radio and sends a messenger in search of the second platoon. Meanwhile, Clemons' men are startled to hear the sound of trumpets blaring, heralding a ferocious assault by the Chinese. When the fighting slows, Clemons finally reaches Ohashi by radio and demands assistance, but Ohashi reports he has lost a quarter of his men and cannot hold his position near the crest if he divides them. Dismayed by the lack of promised support along the hill's left flank, Clemons orders a small squad to provide machine gun cover there. Later, when the nearly decimated squad returns to report to Clemons, he contacts Davis to complain bitterly about the lack of assistance. Davis insists that the crest be taken as soon as possible and ignores Clemons' protest that he has too few men to accomplish the task. Ohashi reports that he has lost nearly half of his platoon and requests the third platoon be activated, but Clemons believes they should be held in reserve as long as possible. Disheartened, Ohashi nevertheless agrees and returns to maintain his position as Clemons is joined by a handful of soldiers dashing up the hill. Clemons is stunned to learn the twelve men are the only survivors from "L" Company, whose two platoons were slaughtered in their attempt to provide delayed assistance to "K" Company. The remainder of Clemons' platoon, joined by the additional men, then rush the next line of trenches and bunker and are relived to find it has already been secured by Ohashi's men. While the soldiers greet one another, the bunker is suddenly hit by numerous artillery shells. Although severely shaken, most of the men survive and angrily insist the shells came from their own side. Realizing the exhausted, demoralized men are correct, and fearing a revolt, Clemons lies, countering that the artillery came from a nearby, Chinese-held mountain. Anxious over the long silence from Davis, Clemons meets with Ohashi to decide upon their next action. Clemons summons Lt. Waldorf and the third platoon and declares the crest must be taken to avoid the continued attrition of the remaining American forces. Knowing that Waldorf is inexperienced, Ohashi volunteers his men to make a risky bayonet charge against the crest. Clemons promises a diversionary action as well as support and the move is successful. Afterward, Clemons radios Davis' headquarters, which have now come under an intensive enemy barrage. Cut off after hearing Pork Chop Hill has been taken at last, Davis is unaware of Clemons' desperate plea for supplies and ammunition. Soon after, "K" Company's last radio is destroyed, but Clemons is pleased by the arrival of his brother-in-law, Lt. Walt Russell, commander of "G" Company. The men's reunion is short-lived, however, when Russell reveals he has been assigned to perform a "mop-up" action and not to reinforce "K" Company. Russell is horrified to learn Clemons and Ohashi have only thirty-five men left from their entire company. Moments later, a messenger arrives with news from Davis that "G" Company has been recalled, as Davis believes the hill secured. Clemons sends a terse return message insisting that without Russell's men, the area cannot be held. At division headquarters, Gen. Trudeau demands to know whether his superiors intend to hold the hill, but nevertheless supports the recall of "G" Company. Russell departs, taking Clemons' wounded and leaving as much ammunition as possible. Clemons orders his twenty-five remaining men to spread out along the crest as the Chinese radio broadcaster informs the Americans they have forty-five minutes to surrender or they will be destroyed. Using the radio left by Russell, Clemons contacts Davis to declare that unless they are provided reinforcements, they must withdraw, but Davis responds that he has received no further orders. At the Panmunjom peace conference, the American representative angrily concludes that the Chinese refusal to give up the strategically useless Pork Chop Hill serves as a test of American character, and contacts American Infantry Division headquarters. As the Chinese begin their final assault on Clemons' position, Ohashi is wounded bringing Clemons a report that "L" Company's surviving platoon is providing support. The strength of the Chinese attack forces the Americans into bunkers that they frantically seal against enemy flamethrowers. The tide then abruptly turns when a reinforcement division arrives to clinch the taking of Pork Chop Hill.