It's been 27 years since Dr. Sam Beckett stepped into the Quantum Leap accelerator and vanished. Now a new team has been assembled to restart the project in the hopes of understanding the mysteries behind the machine and the man who created it. Dr. Ben Song, lead physicist of the top-secret government time-travel program known as Quantum Leap, makes an unauthorized leap into the past, awakening in a different body with only fragments of his memory intact. Guided by Addison, a colleague in the present day who appears to him as a hologram that only he can see and hear, he discovers the only way for him to leap again is to correct something in his host person's life. As Ben leaps from life to life, putting right what once went wrong, his team in the present tries to figure out why he leaped and bring him home.