The First Protectors

When Ben Shepherd left the Navy SEALs, all he wanted was to spend his retirement resting his battered body and finding peace for his wounded spirit.
That all ends when the starry desert night is shattered by an alien ship crashing to Earth near his remote home. The pilot is the last of a conquered civilisation, shot down by extra-terrestrial aggressors. Another war has found Ben, and when he is injected with a serum that gives him superhuman abilities, it's a war he has no choice but to fight for the sake of the planet.
His body might be healed, but his trauma still weighs heavily on him as he becomes the reluctant leader of the only line of defence against an alien invasion. Will his broken psyche be able to stand the pressure? And what becomes of the Earth if it can't?