Highlights from the Thirteenth Episode of Season 4 of NCIS: LA

Pictured: Chris O'Donnell (Special Agent G. Callen). Callen goes undercover to infiltrate a network of Chechen terrorists who are recruiting foreign fighters to join their cause and planning their next attack in the U.S. Photo: Cliff Lipson/CBS ©2013 CBS Broadcasting, Inc. All Rights Reserved.

Pictured (L-R): Chris O'Donnell (Special Agent G. Callen), LL COOL J (Special Agent Sam Hanna), Eric Christian Olsen (LAPD Liaison Marty Deeks), Daniela Ruah (Special Agent Kensi Blye), Linda Hunt (Henrietta "Hetty" Lange), Barrett Foa (Tech Operator Eric Beale), and Renée Felice Smith (NCIS Intelligence Analyst Nell Jones). Callen goes undercover to infiltrate a network of Chechen terrorists who are recruiting foreign fighters to join their cause and planning their next attack in the U.S. Photo: Richard Cartwright/CBS ©2013 CBS Broadcasting, Inc. All Rights Reserved.

Pictured (L-R): Linda Hunt (Henrietta "Hetty" Lange), Barrett Foa (Tech Operator Eric Beale), and Renée Felice Smith (NCIS Intelligence Analyst Nell Jones). Callen goes undercover to infiltrate a network of Chechen terrorists who are recruiting foreign fighters to join their cause and planning their next attack in the U.S. Photo: Richard Cartwright/CBS ©2013 CBS Broadcasting, Inc. All Rights Reserved.

Pictured (L-R): Chris O'Donnell (Special Agent G. Callen) and LL COOL J (Special Agent Sam Hanna). Callen goes undercover to infiltrate a network of Chechen terrorists who are recruiting foreign fighters to join their cause and planning their next attack in the U.S. Photo: Richard Cartwright/CBS ©2013 CBS Broadcasting, Inc. All Rights Reserved.

Pictured: Barrett Foa (Tech Operator Eric Beale). Callen goes undercover to infiltrate a network of Chechen terrorists who are recruiting foreign fighters to join their cause and planning their next attack in the U.S. Photo: Richard Cartwright/CBS ©2013 CBS Broadcasting, Inc. All Rights Reserved.

Pictured: LL COOL J (Special Agent Sam Hanna). Callen goes undercover to infiltrate a network of Chechen terrorists who are recruiting foreign fighters to join their cause and planning their next attack in the U.S. Photo: Richard Cartwright/CBS ©2013 CBS Broadcasting, Inc. All Rights Reserved.