The story begins at around the same point as “Mechanicum” and converges with the Malcador “Knight Errant” plotline. This story follows members of the Legion who had been sent to Mars to train as Tech-Marines. But with a Martian Civil War underway, and the Fabricator General sworn to Horus, the forces of Mars have decided it best to wipe the Marines off the surface of Mars.
The main protagonist, Dravion Klayde “The Carrion” is of the Raven Guard Legion, but a battle against vicious Xenos cost him an arm and two legs. The bionic replacements were considered too cumbersome and noisy by his brothers, who valued stealth above all else. So, he was sent to Mars, to learn the ways of the Machine Cult. It’s a strong hook to begin the story, he was cast out for not meeting the requirements of his Legion and so he is left feeling like he doesn’t belong anywhere.
The action is intense but easy to follow. It also works well on an emotional level. The Space Marines are confused and furious at the betrayal, they don’t know if this factionalism or if all of Mars has turned against Terra.
The second portion of the story begins on Terra. Zagreus Kane, the leader of the loyal Mechanicum faction appears alongside Rogal Dorn and Malcador, which treats us to a fantastic debate as they consider the future of Mars.