At the start of the Tet Offensive, a Marine Long Range Reconnaissance unit led by Sgt. Maj. Bill Hafner [R. Lee Ermey] and Cpl. Joseph L. "Nard" DiNardo [Wings Hauser] comes across a village where locals have been gruesomely executed for fraternizing with the US troops. DiNardo discovers the sole survivor, a young Vietnamese child [Michael Cruz], and the team presses on. On patrol, they stumble upon a Viet Cong tunnel complex and uncover an American POW, a discovery that intensifies the stakes of their mission. The Marines then push toward the firebase known as Gloria, a poorly defended outpost that will soon be tested to its limits. Hafner takes charge the moment he learns that the base’s commanding officer, Captain Williams [John Calvin], is a burned-out drug addict who is not fit for duty, a revelation that compels Hafner to reorganize the defenses and assume direct responsibility for the precarious outpost.
Hafner and DiNardo forge a tight, formidable partnership, inspiring the troops to steel themselves for a major offensive. Hafner even reaches out to a wandering photographer to bolster morale, bringing in Nick Nicholson to document the coming fight and, more importantly, to remind the men of their humanity amid chaos. The base’s medical staff and nurses are present, but Hafner’s instinct is to keep the hospital from becoming a target; still, Captain Kathy Flanagan, MD Margaret Gerard proves more capable and steadfast than the embattled Williams, earning the trust of the wounded and the weary alike. DiNardo warns Flanagan that the Vietnamese will show no mercy if they breach the hospital, a warning that colors every decision as the siege intensifies.
The Viet Cong escalate their assault, and Hafner and his men fend off a series of brutal attacks. As casualties mount, DiNardo’s resolve begins to crack under the brutal realities of war, even as Hafner explains that DiNardo was once a high-ranking NCO who lost rank after going AWOL when his son died. The recon team loses allies one by one, and the fight becomes a grueling test of endurance and loyalty. Murphy and Shortwave are killed, leaving the survivors to press on under relentless pressure. An Army Air Cavalry unit, led by Captain A.J. "Bugs" Moran, delivers supplies and air support, but the Marines are still surrounded and vastly outnumbered.
In the final onslaught, the medical quarters are breached and, just as DiNardo warned, Flanagan’s patients and nurses are mercilessly executed while she and another patient mount a desperate defense. Even with air support, the base teeters on collapse as the Viet Cong push forward. DiNardo is mortally wounded in a last-ditch effort to safeguard a young boy, and the Viet Cong commander claims the child for his own. Murphy and Shortwave fall in the chaos, and the remaining Marines fight to hold Gloria as long as they can. DiNardo, unable to bear returning home in his condition, asks Hafner for a mercy killing, a moment that seals the grim toll of the battle.
In the end, the Viet Cong commander discovers that his own mission was not to win a victory over the Americans but to drive his men toward suicide, clearing the way for the North Vietnamese Army to assume a larger role in the war. Hafner clarifies that the Tet Offensive inflicted staggering losses on both sides, with more than 55,000 Viet Cong casualties, and the Americans are forced to abandon the base after paying an immense price in life. Hafner clutches his friend’s dog tags in a quiet, heartbreaking moment, whispered through the ache of loss: End of the story, Nard.
