"NCIS: L.A." season 7 continues to hook fans as it never runs out of hope and drama. While news about the upcoming episodes remain so limited, fans of the series wallow in the recent confirmation that it will be renewed for an eighth season.

Episode 20 of "NCIS: L.A." season 7 saw the team assigned to protect the commander of the Pacific Command while tracking down a spy from North Korea to address an international crisis. Fans of the series were also lucky to see actors Corey Sorenson and Andrew Traver guest-starring as NCIS Special Agent David Prieto and NCIS Special Agent Gates.

While the end of the episode showed that the team succeeded in smoking out the North Korean mole, Sam, Callen and the other team members will have to work on an even bigger mission in episode 21.

Titled "Head of the Snake," episode 21 will follow the team as it tries to expose the truth behind the mysterious operational psychologist named Nate Getz. In the episode, the team will learn of his connection with a notorious crime leader after he fails to check in with Hetty while working undercover.

Trailer for the upcoming episode is still unavailable, but photo stills for episode 21 show that some members of the team might be in trouble during the mission. In one of the photos, Callen is shown fastened in a chair while being interrogated.

"NCIS: L.A." season 7 is just four episodes away from its finale. Its 21^st episode will be aired on April 11 on CBS.