The war for humanity's future is being fought in its past.

Across the centuries, a battle rages that no one can see. The weapons are invisible. The soldiers move through time like ghosts. And what is at stake cannot be measured in lives but in the existence of life itself.

On one side: a shadowy force of future humans, working in secret to correct the moments that lead the world toward total destruction. On the other: the Silent-Unseen, survivors of Earth's last great war, who believe the apocalypse was always meant to happen.

Now, a small group of unlikely travelers from the present day has stumbled into the middle of it. . .and the war won't let them stay neutral. They will have to choose between a future that was saved and one that was always meant to burn.

Time doesn't care who wins. But humanity always has, and that may be either its greatest weakness or its only hope.