NCIS: Los Angeles will be going deep when the drama resumes for season 6.

Kensi Dons Hazmat Suit For 'NCIS: LA' Season 6, Chris O'Donnell Directs

Quickly sinking beneath the ocean waves, Sam (LL Cool J) and Callen (Chris O'Donnell) were left in an incredibly perilous situation at the end of May's "Deep Trouble." Picking up where the finale left off, next September's premiere will follow the partner's deadly encounter with terrorists as they continue to drift farther away from the help of Deeks (Eric Christian Olsen) and Kensi (Daniela Ruah).

Directed by Dennis Smith ("The Livelong Day," "Between the Lines"), "Deep Trouble: Part 2" will also continue to follow the Deeks-Kensi-Talia debacle while Hetty's (Linda Hunt) job hangs in the balance and Sam and Callen's bomb laden sub quickly begins to take on water.

Densi Drama Spills Over Into 'NCIS: LA' Premiere? Who Is Kensi Bonding With?

"Awesome week on #NCISLA," Smith tweeted as the CBS series plowed into premiere filming before wrapping work on season 5. "They gave me great script, a submarine, helicopters and a chick fight! Happy Director :-)"

If you are anxiously awaiting the return of NCIS: LA, now may be the time to remind your DVR that Callen and Co. will be moving to Monday nights at 10 p.m. ET when CBS launches its new fall schedual.

Click through the videos above to get a glimpse at "Deep Trouble: Part 2"