It is the year 2046, and the first mission from Earth back to the Twelve Colonies is approaching the halfway point. The two largest Battlestars ever constructed are leading a fleet that will begin the process of bringing civilization back to those worlds. The Fleet is approaching a planet that is known back on Earth as Kepler 452b, also called "Earth's Cousin". A scouting mission is launched to observe the planet, and they discover a terrible truth: Kepler 254b is the Cylon Earth that Galactica visited more than twenty-five years earlier.