The Great Betrayal is the fourth book in the epic series set in the Star Crusades universe that chronicles humanity is first steps away from Alpha Centauri and beyond.

The ancient prophecy spreads to the colonies of the Alliance and ignites a public debate on the rumor of the coming comet. The origins of the rumor revolve around the dark days of the last war fought on Helios. The prophecy speaks of the return of the  Great Enemy that will be signaled by the coming of a burning star, when its beasts and machines will devour entire worlds.