As Commander Spock, his father, Sarek, and Captain James T. Kirk struggle to preserve Vulcan's future, the planet's innermost secrets are laid before us, from its beginnings millions of years ago to its savage prehistory, from merciless tribal warfare to medieval court intrigue, from the exploration of space to the development of o'thia -- the ruling ethic of logic. And Spock -- torn between his duty to Starfleet and the unbreakable ties that bind him to Vulcan -- must reconcile both his own inner conflict and the external dilemma his planet faces...lest the Federation itself be ripped asunder.