Fifty years ago, the International Space Marine Corps (ISMC) fought and won a narrow victory against a vicious foe. Now, Fleet Transport 'Astral Plane' is transporting survivors of this battle when a garbled warning is received, followed by orders from the President of the United Nations of Terra. Her orders are simple: Unconditional surrender, or die.

Abner Fortis and the other Space Marines on 'Astral Plane' aren't about to surrender, but what can two hundred aged ISMC veterans on an unarmed Fleet transport do against overwhelming hostile forces?

It's no coincidence their motto is DINLI. Do It, Not Like It.

They just have to figure out how.