A battle-weary Marine is assigned to guard - and ultimately befriends - a young Navajo soldier who has been trained to be a code talker. This code, the Navajo code, and the men who knew the code, were to be guarded as they went into action. It was the unspoken duty of the Marine to kill the Navajo soldier before he could be taken prisoner of war by the Japanese. This is the one wartime code that was never broken by the enemy.