From NBC's official press release:

Mike (Justin Bruening) and KITT (voiced by Val Kilmer) are trying to track down a stolen serum that maximizes the recipient's physicality before it gets into the wrong hands. With the help of the lab's research assistant, Billy (Paul Campbell) learns some information about the serum that will help Mike when he takes on the now powerful thief. Meanwhile, Sarah (Deanna Russo) is overwhelmed with her new duties and quickly learns how much work it will take to reinstitute the Foundataion for Law and Government. Smith Cho stars. Kevin Alejandro and Mini Anden guest star.

Knight Rider stars Justin Bruening as Mike Traceur, Bruce Davison as Charles Graiman, Deanna Russo as Sarah Graiman, Paul Campbell as Billy Morgan, Sydney Tamiia Poitier as Carrie Rivai, Val Kilmer as KITT (Voice) and Yancey Arias as Alex Torres.


Source: NBC
(Image courtesy of NBC)