On the moon Titan the Great Exchange has taken place. Guardians and Environs are working together. One thing is wrong. Three Metaphors have escaped back to Earth to recruit others to destroy Titan. Guardians and Environs get word of it. Jonathan Thatcher along with some of the other Guardians and Environs will be going back to Earth. In the meanwhile the rest of titan help to set up defenses; to keep Titan safe. Will the Guardians and Environs succeed in their mission to stop the invasion of Titan? See what happen to titan and Earth in the exciting Sci-fi book, Safe at Last.