Kensi (Daniela Ruah) and Deeks (Eric Christian Olsen) might be happily engaged but when NCIS: Los Angeles returns for Season 9, they're going to face a slew of problems thanks to their new boss, Shay Mosely (Nia Long).

The former Secret Service agent — who is stepping in as Assistant Director for Hetty (Linda Hunt) who has gone off the grid after Granger's (Miguel Ferrer) disappearance — is not as forgiving as their previous boss about workplace romances.

"As tolerant as Hetty was for their relationship, Assistant Director Mosely is much more rigid in her thinking about workplace romance, especially amongst one person who doesn't really even belong there," showrunner R. Scott Gemmill tells TV Guide. "She actually, in the first episode, takes steps to see that Deeks is returned to LAPD." If Mosely gets her wish, Denzi will have a much more difficult time planning their upcoming nuptials.

Nia Long Joins NCIS: Los Angeles

Meanwhile, Sam (LL Cool J), who is still grieving the loss of his wife, will need to decide if his time away from the job will be temporary or permanent. "He's trying to figure out what he really wants to do, and it continues into subsequent episodes as he slowly makes some life choices to move forward in a way that is a little bit of a surprise to Callen (Chris O'Donnell)," Gemmill added.

Watch the drama unfold when Season 9 of NCIS: Los Angeles premieres Sunday, Oct. 1 at 9:30/8:30c on CBS. The following week, it returns to its regular time at 9/8c.

(Full disclosure: TVGuide.com is owned by CBS.)

Eric Christian Olsen, Daniela Ruah, NCIS: Los AngelesEric Christian Olsen, Daniela Ruah, NCIS: Los Angeles