In a world very similar to ours, there are children who do not age. They're known as "Kildren," and they're fighting a war. Against whom, and to what end is not important. One such boy, a young fighter pilot named Yuichi Kannami, arrives at his base out in the country, assigned to a small battalion. He's never met these people before, but soon finds himself in an alarmingly familiar routine, acting out relationships that seem predestined. Of course, this has all happened before.