Horizon of the Void
One million years ago, the First ruled the galaxy. A powerful race that went unchallenged all of their reign, they came to power due to their discovery of the most important aspect of their technology and lives. The Void, an extradimensional plane that exists outside but parrellel to our own, and has the unique property of being able to command the molecules of our dimension.
With access to this dimension, and physical pieces of it that naturally fell into our own, the First mastered space travel far beyond anyone of their time. The Void became such a core aspect of their lives that they even began to change on a genetic level, allowing some the ability to manipulate particular molecules with their will alone. Then, as quickly as they rose and ruled, it came crashing down, leaving no evidence of what occurred beyond the vaguest of hints.
For a million years, the Void was forgotten and never rediscovered. Now, civilizations across the galaxy have begun to discover pieces of the Void once more. Space travel and technology has exploded in advancement, and the genetic ability to command molecules has returned in every race in the galaxy. No one knows why this has occurred, few even know it was lost at all. Those that do know wonder, what caused the collapse of the First? Why has the Void been lost to them for all this time? Above all they worry, will it happen again?