Sam leaps into a young woman who was raped after her third date with a boyfriend. Her family is sad for her but embarrassed at what the townspeople think of her. It seems that Sam's mission is to help Katie win the case, but there may be more to this leap than Sam thinks.
The Science of Leaping
In "Shock Theater," Dr. Verbeena Beeks had been unable to communicate with Sam while in the Imaging Chamber. They could see each other, but Sam couldn't hear Dr. Beeks. In this episode, a breakthrough is made so that Sam can hear Katie when she's brought into the Imaging Chamber. The need for Katie to enter the Chamber is so that Sam can testify under oath accurately and honestly as Katie. Sam wouldn't be able to tell the events of the night himself since he wasn't there. But with Katie in the chamber, Sam simply recites the words that Katie says.
Errors in Episode Description
The Quantum Leap Book by Louis Chunovic claims that Katie's last name is O'Donoughue rather than McBain. It also claims that "Kevin Wentworth (the guy who raped Katie) is convicted but released on his recognizance to prepare his appeal. . . . Al reports that Wentworth gets the maximum sentence and that Katie recovers and becomes a D.A." None of this happens in the final episode. Warning: Spoilers ahead. In the episode as aired, Sam is still unsuccessful as Katie to win the case, leaving Sam wondering why he was there at all. However, Wentworth then attempts to rape Katie again, but Sam, with his own strength, pushes Wentworth back and beats the stuffing out of Wentworth, realizing that this is what he was here to do: to prevent Wentworth from trying to rape Katie (or anyone else) ever again. After Wentworth is beat to the ground, the rest of the family comes out and sees what happens, calling the police. The pride in the family name has been restored, with Sam saying to the dad, "After all, I am a McBain." Sam then leaps without Al mentioning what happened to Katie after that, but presumably her future is a good and safe one.