The Point of Divergence comes in early 1941, when Minoru Genda convinces Isoroku Yamamoto that an attack on Pearl Harbor is not enough, and that all of Hawaii should be taken, thus giving Japan an extra layer of security for its conquests from U.S. attack. Yamamoto agrees, and plans are drawn up for the invasion. As in OTL, Japan initiates war with the United States by attacking Pearl Harbor, and Admiral Chuichi Nagumo agrees to invade. From here the novel depicts the hard fought battle for Oahu, as American forces fight futily into February, 1942 before they surrender. The book also addresses the impact on civilians, and looks at the conflict between Sansei and Nisei Japanese living in Hawaii.