Invasion
Kira, was with her father, mother and little brother outside the house when they were attacked by strange beigns(aliens).
Her father and mother ran fast into the room to hide her and her brother when they both died (Her father and mother). She and her brother stayed in the basement until they were saved by a scientist who seemed to know more about about the aliens. He took them to his facility and fed them and then took them to bed.
He then thought of raising his own army against the alien race as he knew part of their weaknesses, he kept on working to create weapons specially designed for the extermination of the aliens and training the kids and some other kids he found.