The Mars colonists get a cold welcome upon their arrival in Mariner Valley. Visions of the colony promised them by the Plymouth Group are replaced with ugly realities as they find themselves confined to a dirty, windowless prison underground, where survival is far from guaranteed.

And the ground crew waiting for them is a collection of angry, tired survivors of ill planning, and there is no hope of return to Earth. Romo, their robotic benefactor, while eager to get on with his own mission, tries to make Mars more livable for his human friends first. 

But their old enemies are still in the skies above, and there are those in the colony leadership who could be just as dangerous. Romo will learn much about human nature, assuming he survives.