Andrew "Ender" Wiggin thinks he is playing computer simulated war games; he is, in fact, engaged in something far more desperate. The result of genetic experimentation, Ender may be the military genius Earth desperately needs in a war against an alien enemy seeking to destroy all human life. The only way to find out is to throw Ender into ever harsher training, to chip away and find the diamond inside, or destroy him utterly. Ender Wiggin is six years old when it begins. He will grow up fast.

In the aftermath of his terrible war, Ender Wiggin disappeared, and a powerful voice arose: The Speaker for the Dead, who told the true story of the Bugger War. Now, long years later, a second alien race has been discovered, but again the aliens' ways are strange and frightening...again, humans die. And it is only the Speaker for the Dead, who is also Ender Wiggin the Xenocide, who has the courage to confront the mystery...and the truth.

The war for survival of the planet Lusitania will be fought in the heart of a child named Gloriously Bright. On Lusitania, Ender found a world where humans and pequininos and the Hive Queen could all live together; where three very different intelligent species could find common ground at last. Or so he thought. Lusitania also harbors the descolada, a virus that kills all humans it infects, but which the pequininos require in order to become adults. The Starways Congress so fears the effects of the descolada, should it escape from Lusitania, that they have ordered the destruction of the entire planet, and all who live there. The Fleet is on its way, a second xenocide seems inevitable.

The planet Lusitania is home to three sentient species: the Pequeninos; a large colony of humans; and the Hive Queen, brought there by Ender. But once against the human race has grown fearful; the Starways Congress has gathered a fleet to destroy Lusitania. Jane, the evolved computer intelligence, can save the three sentient races of Lusitania. She has learned how to move ships outside the universe, and then instantly back to a different world, abolishing the light-speed limit. But it takes all the processing power available to her, and the Starways Congress is shutting down the Net, world by world. Soon Jane will not be able to move the ships. Ender's children must save her if they are to save themselves.