Both versions of the story take place in the future, many years after an invasion of insect aliens attacked the Earth and nearly eradicated the entire human race. The last invasion failed, and was wiped out only by a last-ditch effort a master strategist, that turned the tide of the war. After everyone thought he had died, Earth needed a new leader. It needed a new master strategist to lead and hopefully end the war, but no ideal candidate had stepped forward. The orbital Battle School began to pick the most spectacular children to train in strategy, to see which would come out to be the best the Earth had to offer, and become the new master strategist Earth needed.
Ender was a third child, with reproductive barriers that limit parents to