Jill Titan and the Secret Weapon - Jill Titan, #3

In a spaceship equipped with a powerful secret weapon, eleven-year-old Jill and her father must try to change the course of a space war. After piloting the ship in a wildly risky raid on the enemy's largest space station, Jill will attempt to rescue a young alien sister and brother. Wherever she goes she is under the threat of capture by the enemy, for she knows the plans of the secret weapon. In the end her choices will decide the fate of trillions of people on thousands of planets.