Yesterday's Son (Star Trek: The Original Series #11; The Yesterday Saga, #1)

Spock discovers his own son--living 5,000 years in the past! With the help of the Vulcan leader T'Pau, Spock gets permission to use the Guardian of Forever, a portal through time constructed by a long-vanished race, to venture into the past. On another trip into history, on the planet Sarpeidon, Spock had loved a woman who could not return with him to the future, and now Spock wishes to see the son she bore him, 5,000 years earlier. But a Romulan attack on the Guardian's planet could interfere, unless the EnterpriseTM can keep the Guardian out of their hands. With the help of the Vulcan leader T'Pau, Spock gets permission to use the Guardian of Forever, a portal through time constructed by a long-vanished race, to venture into the past. On another trip into history, on the planet Sarpeidon, Spock had loved a woman who could not return with him to the future, and now Spock wishes to see the son she bore him, 5,000 years earlier. But a Romulan attack on the Guardian's planet could interfere, unless the Enterprise TM can keep the Guardian out of their hands The Romulans attack the planet Gateway, where Federation scientists are studying the Guardian of Forever -- the mysterious portal to the past. The Starship Enterprise TM must protect the Guardian -- or destroy it. But Spock has already used the portal to journey to the past. On the planet Sarpedion, 5,000 years ago, Spock knew a beautiful, primitive woman. Now he has gone back to meet his son! The Romulans attack the planet Gateway, where Federation scientists are studying the Guardian of Forever - the mysterious portal to the past. The Enterprise must protect the Guardian - or destroy it. But Spock has already used the portal to journey to the past. On the planet Sarpeidon, 5000 years ago, Spock knew a beautiful, primitive woman. Now he has gone to meet his son! Our current assignment of charting Sector 70.2 of this unexplored quadrant has been proceeding uneventfully-so uneventfully that I've been resorting to simulated battle drills and abandonship exercises to keep up my crew's efficiency. While the Enterprise is protecting a portal to the past, Spock uses it to travel 5,000 years in the past to meet his son