Back on Earth, the beginning and end of all things. The nations of humanity's home planet have parted ways with the starfaring Colonial Union, the human interstellar empire originally established to keep the home planet free. The Union needs to regain Earth's trust. The alien races of the Conclave have their own hard choices to face. All of these threads culminate in this, Part Four of the four parts of The End of All Things, John Scalzi's conclusion to the Old Man's War tale that began with The Human Division.