The popular CBS police procedural drama, 'NCIS: Los Angeles', will be returning on the air to start its Season 6 with an episode entitled, "Deep Trouble, Pt. II."

The premiere episode will revolve around Callen and Sam who are held hostage by terrorists in a submarine, and Hetty who has embarked on a dangerous trip to Washington.

The showrunner, Shane Brennan, provides some details about what awaits Hetty in the season premiere.

"The story takes Hetty to Washington, where she faces some very hostile questioning from a Senate committee trying to get to the truth of what happened in Afghanistan and whether Hetty was acting outside her job description, so to speak. And then we discover there's more to this, that in fact Hetty is being targeted by someone. And that actually puts her life in danger," Brennan told TV Line.

With the showrunner's revelation, it seems that the upcoming season will showcase a lot of action and undercover operations. It only seems fitting for the show, especially since it has transferred to a new time slot where it will compete with ABC's 'Castle' and NBC's 'The Blacklist' for viewership ratings.

"We are going to make the show as noisy as we possibly can," said Brennan.

The showrunner revealed that going up against two other popular shows is a challenge that 'NCIS: Los Angeles' will not back down from.

"The writers, the cast and the crew have always operated at 100 percent. We've never backed off on anything, and we're not backing off now in any way," said the showrunner.

Meanwhile, this season will feature Callen in a relationship with another character.

While the agent was known to have a rarely seen girlfriend in Season 5, Callen will end up being romantically involved with one of the well-known characters over the upcoming season. It is said that the identity of Callen's new girlfriend will be revealed in the latter part of the season.

The sixth season of 'NCIS: Los Angeles' premieres on Sept. 29 at 10 pm ET on CBS.