Spensa's world has been under attack for hundreds of years. An alien race called the Krell leads onslaught after onslaught from the sky in a never-ending campaign to destroy humankind. Pilots are the heroes of what's left of the human race. She dreams of becoming a pilot, but her fate is intertwined with that of her father-- a pilot himself who was killed years ago when he abruptly deserted his team. When the Krell double their fleet, this may be Spensa's chance to get into Flight School. -- adapted from jacket.