Trilogy Part III: The Last Door was the 10th episode of Season 5 of Quantum Leap, also the 85th overall series episode. Written by Deborah Pratt, the episode, which was directed by James Whitmore, Jr., originally aired on NBC-TV on November 24, 1992.
Sam leaps into a Lawrence "Larry" Stanton III, a lawyer who defends Abigail Fuller on trial for the murder of Leta Aider, the woman who accused her of killing her husband Bart Aider and daughter Violet Aider twenty-three years earlier. Secrets are revealed, the family history comes unraveled, and surprises are in store for Sam as he discovers the heritage behind Abigail's daughter, Samantha Jo Fuller.
July 28, 1978 - In the third final installment of a three-part saga, Sam leaps another 12 years into the future to 1978 and into the body of Larry Stanton, a retired lawyer who was there in 1966 when Abigail Fuller was almost lynched. Abigail has now been charged with murdering Leta Aider, the woman who has always accused her of killing both her daughter and her husband. Aider was found lying in a pool of blood with her throat slit in Abigail's kitchen.
Abigail has specifically asked for Stanton to defend her and despite the attorney's frail health, he decides to do so. Al tells Sam that unless he can change history, Abigail will be found guilty and be executed. Sam also meets Abigail's daughter, Sammy Jo, a very intelligent young girl who Al says is likely Sam's daughter. Sam soon realizes that in order to properly defend her, he will also have to deal with the allegations that Abigail also killed her 12-year-old classmate. For the truth, he turns to Abigail's mother who has been institutionalized for many years.