The novel is set in 1963, eighteen years following the end of the alternate World War II shown in the Worldwar series. Earl Warren is President of the United States, Vyacheslav Molotov is the Premier of the Soviet Union, and Heinrich Himmler leads Nazi Germany. At the start of the novel, the colonization fleet of the Race enters the Solar System, bringing with them, forty million colonists for settling on Earth. As the fleet enters Earth orbit, a human satellite unleashes a nuclear attack that kills millions. As Germany, the USSR, and the United States each have large-scale space capability, either nation may have been responsible for the attack. In addition, while there is peace between the independent human nations and the Race, Mao Zedong and Ruhollah Khomeini continue to lead popular resistance to the invaders in China and the Middle East, respectively. Meanwhile, the Race colonists, who expected to encounter an Earth that was already conquered with the natives still at medieval levels of advancement, have to deal with the consequences of the cold war with the humans. The fleet brings with it not only the first civilians, but also the first Race females, both of which cause tension among the male soldiers who formed the invasion force. To the Race males, ginger is a euphoric drug; to the females, it causes them to go into estrous, resulting in wide-scale social implications