In 1965, at the onset of the Vietnam War, Lt. Col. Hal Moore, a dedicated and strategic U.S. Army officer, is tasked to lead the first major ground battle of the war. Alongside him, war photographer Joe Galloway is intent on capturing the essence of the conflict. Moore trains his soldiers rigorously, instilling both the sense of brotherhood and the harsh reality of the battle they are about to face. He promises them that he will be the first to set foot on the battlefield and the last to step off, ensuring that none of his men will be left behind. His unit, the 7th Cavalry Regiment, is set to land at La Drang Valley, dubbed "The Valley of Death," where they must hold their ground against overwhelming North Vietnamese forces.

In the U.S., the families of the soldiers, primarily focused on Moore's wife Julie, brace for the inevitable news the war may bring, forming a strong community back home. As Moore's men touch down in La Drang, they quickly find themselves surrounded. Their position is precarious, yet Moore's leadership and strategic acumen give them a fighting chance. They establish a perimeter while constantly facing waves of enemy attacks. Military and personal valor, the bonds between soldiers, and the toll of warfare become the heart of their struggle, as they fight for survival in a battle that will test their limits and shape the course of the war.