Thirteen hundred gates have opened to solar systems around the galaxy. But as humanity builds its interstellar empire in the alien ruins, the mysteries and threats grow deeper. In the dead systems where gates lead to stranger things than alien planets, Elvi Okoye begins a desperate search to discover the nature of a genocide that happened before the first human beings existed, and to find weapons to fight a war against forces at the edge of the imaginable.

But the price of that knowledge may be higher than she can pay...