The flesh is weak. The machine is perfect. All of the Iron Hands Space Marines know this to be true, and none better than Atraxii, a gifted pilot of the Clan Company Kaargul. He returns to Medusa as a newly ordained Techmarine, only to be thrust into a conflict that will test not only his flesh, but also his most strongly held convictions. As the pilots of Medusan Wing scramble to defend an Adeptus Mechanicus refinery against ramshackle greenskin squadrons, what secrets are their allies hiding from them? And will the Iron Hands be able to transcend their weakness?