Humans had already conquered space. Even though it's easy to travel to the farthest galaxy, we always thought Earth would be our home.

But we were wrong.

And we had to leave.

Fifteen years after Earth, Cale Tucker still remembers the invasion of the alien Drej -- but with human survivors scattered across the galaxy, he has forgotten how to dream. Until he discovers a map left for him by his brilliant scientist father. A map that reveals the location of a legendary spacecraft known as Titan. Where did it come from? Why was it built? And what secrets were hidden inside? As this riveting journey unfolds, Cale will discover that he must find these answers -- because he himself is humanity's last hope.