The Sol Invasion (Lagrange Trilogy)

Humanity has grown to encompass the moons and planets of Sol, and many artificial colonies have been placed at specialized positions of neutral gravity called: Lagrange Points. However, wars have caused the people of Sol to only colonize out to Saturn, and never have left their home system. In the eras of peace, instead of innovation there has been stagnation. Now, another race of beings have declared humans as unworthy of the stars and intend to eliminate all life in Sol.

Ace pilots Waltz and Fencer explore life in the outer core, as society changes to defeat this ever-present threat. Roth, Waltz' little sister and the first friend Fencer has ever made on her own, meanwhile decides to live her life to the fullest, regardless of the consequences.