Things will be pretty intense for the police officers of "NCIS: Los Angeles" as a double agent infiltrates the headquarters in the upcoming episode of the series.  The official synopsis for episode 9 titled "Traitor" reads: 

"Hetty is going to order a lockdown after Granger is poisoned by the mole and Eric is going to become one of the seven suspects in the case." 

The very dramatic episode will show Hetty Lange (Linda Hunt) being forced to close the headquarters to investigate who among the team tried to poison Owen Granger (Miguel Ferrer). All characters also conduct their own investigations to find out who among them has a dangerous motive. Chaos, suspicions, and discord envelope the team in an attempt to discover who the culprit is.

One of the suspects in the crime is Eric Beale (Barrett Foa), whose loyalty is in question because of the recent turn of events. The NCIS tech operator may be facing a tough time this week, and times will be rougher for him if the traitor is not caught soon. 

This episode also features several guest stars, including Sarayu Rao who portrays the role of Dr. Susan Depaul, as well as Parry Shen as the character named Ty. 

"NCIS: Los Angeles" is a spin-off of the police procedural and military drama series NCIS. It began its first season on Sept. 22, 2009. 

The main cast is composed of Chris O'Donnell who portrays the role of Special Agent-in-Charge G. Callen, Daniela Ruah as Special Agent Kensi Blye, Hunt as Operations Manager Hetty Lange, Foa as technical operator Eric Beale, Ferrer as Assistant Director Owen Granger, Adam Jamal Craig as probationary agent Dominic Vail, as wel as LL Cool J as Sam Hanna. 

"NCIS: Los Angeles" season 6 episode 9 is scheduled to air on Monday, Nov. 24, on CBS network.