War dogs - Greg Bear

An epic interstellar tale of war from a master of science fiction.

One more tour on the red. Maybe my last.

They made their presence on Earth known thirteen years ago.

Providing technology and scientific insights far beyond what mankind was capable of. They became indispensable advisors and promised even more gifts that we just couldn't pass up. We called them Gurus.

It took them a while to drop the other shoe. You can see why, looking back.

It was a very big shoe, completely slathered in crap.

They had been hounded by mortal enemies from sun to sun, planet to planet, and were now stretched thin -- and they needed our help.

And so our first bill came due. Skyrines like me were volunteered to pay the price. As always.

These enemies were already inside our solar system and were moving to establish a beachhead, but not on Earth.

On Mars.