Theorizing that one could time travel within his own lifetime, Dr. Sam Beckett stepped into the Quantum Leap accelerator and vanished... He woke to find himself trapped in the past, facing mirror images that were not his own and driven by an unknown force to change history for the better. His only guide on this journey is Al, an observer from his own time, who appears in the form of a hologram that only Sam can see and hear. And so Dr. Beckett finds himself leaping from life to life, striving to put right what once went wrong and hoping each time that his next leap will be the leap home.

Professor Vandemeer works on a secret project for the US-Air-Force called DART: a very small helicopter for scouting and defense. When he gets killed, Colonel Denton gets under suspicion. His son Scott and Vandemeer's daughter Karen believe in his innocence and search for the true murderer and his motives.