Nothing is ever set in stone until the cameras start to roll on NCIS: Los Angeles.

'NCIS: LA' Season 7: Premiere Title Announced, Will Tony DiNozzo Really Feature?

Just days before filming is expected to begin on episode 702 (airing order unconfirmed), writer Dave Kalstein has announced that the upcoming storyline will no longer be called "Aegis."

"...and sometimes I feel like changing an episode's title 2 days before shooting just to keep things interesting," Kalstein tweeted on Thursday, swapping out the original title for "Citadel."

'NCIS: LA' Season 7: Deeks Takes A Tumble [PHOTOS], Is Kensi To Blame?

Spoilers for the plot, however, are few and far between. Since "Aegis" referred to the protection or support of a person or organization and a "Citidel" could serve much the same purpose, it appears the Office of Special Project may have their hands full keeping someone - or something - safe.

Currently, the NCIS: LA cast is busy filming the season premiere. Titled "Active Measures," the season 7 opener will air on Sept. 21. While "Active Measures" will be the first episode to hit screens, the CBS drama also filmed two episodes last May. One, which features NCIS star Michael Weatherly, will air in October. No date has been announced for the other installment, which was directed by Chris O'Donnell (Callen).

Catch up with Callen, Deeks (Eric Christian Olsen), Kensi (Daniela Ruah), and Sam (LL Cool J) Mondays at 10 p.m. ET on CBS. Click below to see a clip from the season 6 finale.

Tags: NCIS: LA NCIS: Los Angeles television CBS