Duty and Devotion

Older sister Nettie wasn't sure what the militia thought she was, but she knew it wasn't a space fighter pilot on the front line. But Dad always pressed the importance of duty to your territory. Now she has to figure out how to survive in a place she never imagined ending up. Keeping things interesting is a very overconfident competitor, James. Through it all, she got her younger sister Rinny. Or she believed until the moment she lost her.
As for Rinny, the Mars facility gives her chances to break family expectation and she thrives in ground combat training. She also learns life off the concert stage can be just as rewarding when she makes her first real friend and meet Daniel, who could might be "the one." He's a little more reluctant and it turns out he has a reason, a secret involving Rinny. After the enemy attacks her facility and kills he best friend, Daniel disappears. Now captured, Rinny must fight behind enemy lines to help her people remain free, and live to return home.