Josh McCann awakes to find that he has become a convicted criminal, sentenced to years of interstellar combat in support of humanity's expansion throughout the universe.
No longer human, he is now a digital facsimile of himself, intended to serve as the brains in a variety of semi-autonomous weapons systems employed by humanity to "clean up" human habitable planets.
His memories of his previous life have been confiscated and access to them is now dependent upon his performance evaluations as a Marine serving in the Universal Synthetic Marine Corps.
Josh struggles to adapt to life aboard a USMC troopship. The constant simulator training, deadly combat missions, and the challenges of navigating a bizarre new social order cause him to question whether he can survive his sentence. The uncertainty of what his life would be like after the USMC has him questioning whether he even wants to.
Things are never as they appear in troopship land thanks to manipulation by the command structure, and the ingenuity of the Marines as they seek to maintain some control over their collective destiny.
Oh, and there's space combat, romance, bromance, social commentary etc.