This week on NCIS, the team has to find a serial killer, and their investigation leads them to a surprising revelation. Meanwhile, McGee tags along with Abby to Mexico, as teased in last Tuesday's "Obsession," where she has to give a presentation.

The topic of Abbs' speech? Forensics in cold cases. The fact that this takes place in Mexico could foreshadow trouble for a certain agent, given what we know from previous seasons.

Here's a promo of tomorrow night's episode, "Borderland" ...

[video url="http://www.tvfanatic.com/videos/borderland-promo/" title="Borderland Promo"] [/video]

Clearly, something she turns up pertaining to our man and he's not happy. But what do you think happens between Gibbs and Abby - and how will it escalate in the next few weeks?

Follow the jump for some NCIS pictures from the episode ...

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