This week on NCIS: Los Angeles, after a Navy SEAL impostor is set ablaze, the team obtains new information regarding the whereabouts of the stolen Brachytherapy canister.

That means the race is on to stop a dirty bomb from being in play.

Also, in a surprising development, Hetty tenders her resignation. It's not clear why, or whether she will be gone for good. But Claire Forlani makes her debut Tuesday night.

Check out the official preview for "Impostors" below ...

It sounds like the twists coming at the end of NCIS: LA's second season are shocking the cast as well as the viewers. Says Eric Christian Olsen (Deeks) of the next two weeks:

"I remember reading this script in the hair and makeup trailer, and getting to the end of it, and I literally jumped out of my seat, ran outside, and I was like, ‘What? What?!’"

"[I started] looking for a producer or someone to tell me what was going on. That’s what’s so much fun about this, is that these guys are telling stories over 100 episodes."

"We get it as the audience gets it, and I still get tons of adrenaline.”

Daniela Ruah (Kensi) agrees: “I think followers of this show will definitely be having panic attacks, and will be looking forward to season 3 to know what the result is.”

What do you think? Will Linda Hunt be back on NCIS: Los Angeles next season, and what other surprises await us as we head into tomorrow and next week's finale?

Steve Marsi is the Managing Editor of TV Fanatic. Follow him on Google+ or email him here.