Dawn of Mankind by John Walker

Commander Cassian Reeve expected his survey run to end the way it always did. Tag the rocks, log the readings, go home.Then object four fifty-three rolls across his display. Its surface reads like ordinary nickel-iron. Its core says something else entirely. Whatever is buried inside that asteroid has been waiting a very long time.Reeve makes one mistake. He tells his crew to drill.The moment the bit touches that ancient shell, a pulse goes out. Somewhere far beyond human space, something old and patient opens its eyes. A silent vessel shifts course through systems no human has ever charted, and another faction, older and far less forgiving, is already closing in.For centuries, humanity believed it was alone. It wasn't. It was simply beneath notice.Reeve came out here to catalog rocks. Instead, he has stumbled onto a galaxy-spanning network that was buried for a reason, and every ancient power that still remembers why is moving to claim it first.Humanity has just stepped onto the galactic stage. And the galaxy has been waiting.