During the final days of the Vietnam War, Navy SEAL Mike Thornton leads a desperate last stand after five men are trapped behind enemy lines in North Vietnam. Outnumbered by an army of 150 soldiers, they fight through relentless enemy fire before making a harrowing retreat into the South China Sea. With both a gravely wounded lieutenant and fellow soldier tied to him, Thornton swims for hours through hostile waters to reach safety, an act of valor that earned him the Congressional Medal of Honor.