Thanks to the accidental triggering of an ancient alien technology, Captain Kirk has been banished to his own past. During a brutal massacre on Tarsus IV, Kodos the Executioner entered the history books as one of the most genocidal tyrants of the twenty-third century. As a boy, Kirk barely survived. Can he stand by now and let it happen again? Lt. Kevin Riley is the only other survivor of Tarsus IV serving aboard the U. S. S Enterprise. His traumatic memories provide Spock's best hope of finding their time-lost captain - before Kirk alters their time line forever!