In November 1944, the U.S. Navy fleet lay at anchor in Ulithi Harbor, deep in the Pacific Ocean, when the oiler USS Mississinewa erupted in a ball of flames. Japan's secret weapon, the Kaiten - a manned suicide submarine - had succeeded in its first mission. The Kaiten was so secret that even Japanese naval commanders didn't know of its existence. And the Americans kept it secret as well. Embarrassed by the shocking surprise attack, the U.S. Navy refused to salvage or inspect the sunken Mighty Miss.