When the Family of Man receives a mysterious message from an unknown brother ship somewhere in the galaxy, a set of actions is set into motion that will lead Earth into a final battle for its own existence. Lisa and John, the original discoverers of the Family of Man discover the message and along with Pnomos, the leader of the Family of Man on Earth, begin setting plans to protect Earth from the eventual arrival of these aliens. John discovers a forgotten mechanism on the obelisk, the communication device of the Family of Man which had been forgotten and never used. The device, the Legacy of Pnomos, was a protector only to be used in a dire emergency if being attacked. As Lisa, John and the Family of Man decipher its use and its significant power, the alien race begins its approach to Earth.