World War II. America is fighting in fierce battles with the Japanese in the Pacific. During this war, the Japanese skillfully decode secret U.S. dispatches. This has made the U.S. government recruit several hundred Navajos to use their native language as a code for secret messages. A Marine Joe Enders is given the task to guard Ben Yahzi, who knows the secret code, to protect him at all costs, and even kill his ward if he gets captured by the enemy. Joe will have to decide whose life to sacrifice - his or Ben's - to protect the code.