When the Colonial Shield Federation needs someone to face an ancient alien threat, they don't call their best; they call the only Marines who survived first contact. Problem is, a decade of hard living has taken its toll on Frank Cage and Martin Kelvin. Frank has spent the last ten years drowning his memories in whiskey and starting bar fights, while Martin walks around on a cybernetic leg, tending his garden and trying to forget the past. But their retirement comes to an abrupt end when a military transport arrives, crushing Martin's prized tomatoes and bringing orders that can't be refused.

Aliens exist...and, as it turns out, most of them aren’t that friendly. Jacob Brown wasn’t even born yet the first time they attacked Earth. He was only 14 the second time it happened. When Earth finally came together and fielded its first spaceborne military, Jacob didn’t hesitate to volunteer. Serving aboard a mighty starship, he’d be able to defend his planet - and his family - when, inevitably, they came again.

Born on a forsaken desert planet, Cole Shaw has two options - perish from starvation and disease, or enlist in the New World Republic’s armed forces. He chooses the military. For the first time, he thinks he has a shot at a better life. But survival is not guaranteed. Leading an elite team of mech operators, he is deployed to a frozen planet called Ferrous where dangerous relics of a past war lurk beneath the ice and savage creatures prowl the barren wastelands. Scientists on Ferrous are chasing rumors of godlike technologies buried in the ruins of a long-extinct civilization.

Two and a half centuries before the Hell Divers, the Machine War erupted—autonomous killer robots turning Korea into a battlefield that threatened to consume civilization. As the dust settles, three men stand at the crossroads of humanity’s fate. CEO Tyron Red, thrust into leadership of the Industrial Tech Corporation after his father’s death, works to reverse the war’s catastrophic effects while battling enemies, both human and machine, lurking in the shadows.

My name is Kazimir Wolfe. People call me "Kaz", except they don’t. I never use my real name; it’s too dangerous, for me and for anyone I meet. I’m on the run from the law, who think I killed my aunt, and from whoever did kill her, because they want to finish the job. So, I move around a lot, working construction or whatever job I can find. It’s a lonely life. I don’t let anyone get close...people who get close to me end up dead. Why? I’m a wizard. The world’s only wizard, as far as I know.