In the next episode of "'NCIS: Los Angeles," agents G. Callen (Chris O'Donnell) and Sam Hanna (LL Cool J) go undercover to investigate stolen weapons.

The trailer for the upcoming installment titled "Plain Sight" was released recently and showed Assistant Director Shay Mosley (Nia Long) briefing Callen and Hanna at the headquarters. Apparently, the weapons that were stolen have a street value of around one million dollars. Moreover, the team was able to track the evidence to a wealthy charity event. This prompts Mosley to attend the event as a guest while Callen and Hanna go undercover as her bodyguards.

Mosley explains, "Livingston Bradford are providing security teams but I told them I have my own." Callen instantly knows what the director has in mind and replies, "What a coincidence. Our schedules just opened up." Hanna nods in agreement but Mosley looks at them from top to bottom and says, "Fantastic. You do know this is a semi-formal event. Step up your game." It seems the two agents need to dress the part as bodyguards in order to look convincing. Mosley is not willing to take any chances. It remains to be seen if their undercover operation will go as smoothly as they planned.

In the last episode, the team was able to stop a couple of Chinese nationals from getting their hands on secret U.S. surveillance reports. Apparently, a Navy Lieutenant smuggled the classified information to get bids from foreign buyers but got killed in the process. Callen and Hanna were able to locate the perpetrators but got all of them killed in a shootout.

Mosley wanted the foreign nationals alive so that they could trace the source's location abroad. Nevertheless, the team still chalked up the operation as a win.

"NCIS: Los Angeles" season 9 episode 4 will air on Sunday, Oct. 22 at 9 p.m. EDT on CBS.