The air was tense as North Vietnamese officials prepared to put Commander Jeremiah Denton in front of television cameras for a propaganda broadcast in May of 1966.

Denton had been a prisoner of war for almost a year, and he was asked to behave and do as he was told. For a while, he obeyed and followed the instructions, but when he was asked about the United States’ involvement in the war effort in Vietnam, Denton went off script and expressed unwavering support for his country, much to the disgust of his captors.

The officials then noticed Denton doing something rather strange: it looked as if the American prisoner was uncontrollably blinking, but he blamed the camera lights and kept going.

In reality, Denton was sending a Morse code message with his eyes, hoping that someone back home would notice. The word spelled ‘TORTURE,’ and it was the first time the entire world realized that the prisoners of war were being severely mistreated by the Communists.

The US Office of Naval Intelligence would readily take action, but so would the North Vietnamese officers who held Denton captive...