Fans of "NCIS: Los Angeles" know that the show always starts off a new season with a bang, and season 7 is no exception as Callen is about to go on a dangerous mission by himself. 

According to the season 7 premiere synopsis from TVLine, Callen (Chris O'Donnell) will be embarking on a secret project, leaving Sam (LL Cool J) and the entire team in the dark. After Hetty (Linda Hunt) demands that his operation be shut down, the team is tasked with finding Callen before he finds himself in deep trouble. 

For now, there's not much information about Callen's secret project, so it is unclear if this is related to a previous case or if it's something personal. 

No mention has been made either about Deeks (Eric Christian Olsen) and Kensi (Daniela Ruah), and fans are eager to see how their new relationship will affect the team's dynamics. However, new challenges await them as Entertainment Weekly reports that Deeks is going to get a visit from his mother, and Kensi will have the opportunity to meet her. 

Mrs. Deeks will be played by "Parks and Recreation" alum Pamela Reed. Executive producer Shane Brennan told EW that it's going to be a "big moment" for Kensi when she meets her boyfriend's mom. The show boss added that it's also going to be a bigger moment for Deeks and "another memorable 'NCIS: LA' moment for the fans as we lift the veil on one of our much-loved characters." 

With Mrs. Deeks' arrival, fans will surely get to know more about Marty's backstory, and this is also going to be a big moment for Deeks and Kensi, given that opening up this part of his past to her is likely to be one of the major points of the season.

"NCIS: Los Angeles" season 7 premieres on Monday, Sept. 21, at 10 p.m. on CBS.