The Lost Aria. Earth Song, #3

After more than five centuries of isolation on Bellatrix, war has come once again. Minu Alma distinguished herself during the Rasa Vendetta, and she has created a combined army of human and Rasa soldiers to defend her world. Though the soldiers are untried, her enemies haven't given up, and she must lead them into battle against one of the premier species of the Concordia in what will be the greatest test of her life. Not only must Minu win, but she knows she must win quickly if she is to venture into the galactic frontier to save her friend.
Somewhere on the frontier is an ancient artifact left by a mysterious race called "The Lost" which could unlock all the miracles of Concordian science and save Pip's life. Time is running out to save her friend, though, and what she finds will change her life forever. This is The Lost Aria.