Sam Hanna's (LL Cool J) former partner, who was branded as a traitor, comes back in the upcoming "NCIS: Los Angeles" season 7 episode directed by Chris O' Donnell, who portrays the role of Sam's current partner Callen.

Based on the details provided by CBS regarding the sixth episode titled "Unspoken," the Office of Special Projects team of the Naval Criminal Investigative Service based in Los Angeles will look for Sam's former partner Ruiz (Anthony Ruivivar), who mysteriously disappeared while buying a high-powered explosive during an undercover mission.

The team wants to find out if the reason why Ruiz went under the radar is his alleged involvement in an illegal trading of dangerous explosives, which he was supposed to investigate in the first place. How will Sam react once he comes face-to-face with his old pal? Will Ruiz clear his name, or will the team prove that their former colleague betrayed them?

Meanwhile, Marty Deeks (Eric Chirstian Olsen) and Kensi Blye (Daniela Ruah) will have to go undercover in the seventh episode of "NCIS: Los Angeles" season 7. This time, the duo must gather more information about a cult that allegedly brainwashes its members.

According to the spoilers, "Kensi and Deeks go undercover as cult members to rescue a former Department of Defense employee brainwashed into revealing classified information, as the rest of the team works to prevent the cult from selling the government secrets."

The cult that Deeks and Kensi will have to deal with is called the Church of the Unlocked Mind that is being led by Lee Ashman (Sebastian Roche). However, they have to work fast in order to protect the classified information gathered by the U.S. Department of Defense from being discovered a Chinese spy.

"NCIS: Los Angeles" season 2 airs Mondays on CBS.