Following the events of Star Trek: The Motion Picture the captain and crew of the USS Enterprise found themselves haunted by their extraordinary encounter with the vast artificial intelligence of V'Ger, and by the sacrifice and ascension of their friend and shipmate, Willard Decker. As James T. Kirk, Spock and Leonard McCoy attempt to cope with the personal fallout of their ordeal, a chapter from their mutual past is reopened, raising troubling new questions about the relationship of God, man and A.I.

On the recently settled world of Daran IV, the former refugees of the Fabrini worldship Yonada are divided by conflicting ideologies, some clinging to their theocratic past while others envision a future governed by reason alone. Years ago the officers of the Enterprise helped overthrow the Oracle, the machine-god that controlled Yonada. Now confronting the consequences of those actions, together with echoes of their strange encounter with V'Ger, Kirk, Spock and McCoy face choices which will decide the fate of a civilization - and which may change them forever.