On the morning of December 7, 1941, Japan's war machine attacked Pearl Harbor, killing over 2,300 American servicemen. The conventional story is that America was caught sleeping that day and was hit without warning. But newly declassified documents from U.S. Naval Intelligence and the FBI reveal a very different tale, one of Japanese and German spies studying Pearl Harbor long before the assault. So, how were we still caught so tragically off guard? Modern historians are determined to find out.