Engines of destiny - Gene DeWeese

In the Star Trek feature film GENERATIONS, engineer Montgomery Scott was on board the Enterprise-B when Captain James T. Kirk was lost in the course of a mission to save the lives of dozens of refugees _" among them an enigmatic woman called Guinan. One year later Scott is propelled seventy-five years into the future to the Enterprise-D where he once again encounters Guinan, now the bartender on the flagship captained by Jean-Luc Picard.
Struggling to adjust to life in the twenty-fourth century, Scott hatches an audacious plan to go back in time and rescue Jim Kirk. But his attempt to save his old friend has disastrous consequences for the timeline and Scott, Kirk and the crew of the Enterprise-D all find themselves in an alternate twenty-third century in which the Federation no longer exists and the Borg have assimilated humanity. The key to restoring the timeline and saving the human race lies with Guinan _" the very person who might be responsible for the timeslip in the first place