Although it's been a while since Pauley Perrette's Abby Sciuto exited "NCIS," the show's 500th episode managed to pay homage to the popular investigator.

Pauley Perrette was a fan favorite for 15 seasons on NCIS before her departure. She later revealed the reason for her split, and it had to do with a co-star.

As NCIS navigates another big cast transition, TVLine ranks the CBS drama's biggest exits ever, and how they shook up the show.

Knight (Katrina Law) is called to a standoff because the man inside will only talk to her — at one point, McGee (Sean Murray) uses a lip-reading program on a video that he reveals he created as a birthday present for Abby (Pauley Perrette,

NCIS star Diona Reasonover, who plays forensic scientist Kasie Hines, reveals the key to the show's 23-year, 500-episode success.