In late 1944, America's naval forces face what seems an insurmountable threat from Japan: immense Yamato-class battleships, which dwarf every other ship at sea. Built in secrecy, these ships seem invincible, and lay waste to any challengers. American military intelligence knows of two such ships, but there is rumored to be a third, a newly-built aircraft carrier, ready to launch from Japan's heavily-defended and mined Inland Sea. Such a ship would threaten U.S. Pacific forces, allow Japan to launch air attacks against the U.S. mainland and change the course of the war.