In August 1939, a trade embargo imposed by the United States is depriving a belligerent Japan of raw materials. Influential Imperial Japanese Army figures and politicians push through Tripartite Pact and make preparations for war. The newly appointed Commander-in-Chief of the Japanese Combined Fleet Isoroku Yamamoto reluctantly orders the planning of a pre-emptive strike on the U.S. Pacific Fleet anchored at Pearl Harbor, believing that Japan's best hope of achieving control of the Pacific Ocean is to annihilate the fleet at the outset of hostilities. Air Staff Officer Minoru Genda is chosen to mastermind the operation while his old Naval Academy classmate Mitsuo Fuchida is selected to lead the attack.