Happy for the McGee family backstory coming up on NCIS, but when are we going to get the Abby arc we were promised? — Tory
ADAM: Soon — like, in-the-first-few-episodes soon! “We’re going to actually get into a story line that’s going to reveal something about Abby’s past and her family that people aren’t going to see coming,” executive producer Gary Glasberg teases. “It’s a revelation that she makes on her part… and it’s going to tee up a mini-arc.” Speaking of family, Glasberg also confirms that both Ralph Waite and Robert Wagner will return this season as Papas Gibbs and DiNozzo, respectively.

Source