Sam Beckett (Scott Bakula) is a brilliant scientist with six doctorates, whose efforts to return to the present following a flawed time-travel experiment keep him bouncing back and forth in time replacing people he never knew or heard of. His partner on the Quantum Leap experiment, The Observer (Dean Stockwell), appears as a hologram only Sam can see or hear. The Observer is an eccentric quantum physicist, ex-astronaut, ex-Golden Gloves boxing champion and womanizer, who assists Sam in adapting to the different time periods and personas. This proves both challenging and amusing, providing high drama as the perplexed hero valiantly tries to live each life he's been forced to assume without any of that person's skills or knowledge. Quantum Leap is the promise of a second chance. With each leap, Sam is given the opportunity to make things right -- change the lives of the people he becomes for the better and in the end, hopefully, make the world a better place.