On Wikipedia, the description for "Borderland" simply states "Abby and McGee stay the night together while hunting for a serial killer." The episode surpassed the description a hundred fold by every stretch of the imagination. It was fast paced, interesting, and set up the conclusion for the season. It's Season 7 and the show isn't slowing down anytime soon.
Abby and McGee travel to Mexico under suspect circumstances. She is there is teach about cold cases, but when members from the Reynosa Cartel show up the episode takes a wonderful turn. The cartel woman hands Abby a casing for a sniper bullet. Further analysis reveals that it was used in the killing of the killer of Gibbs's wife and daughter. And there is something else afoot Abby is informed late in the game and her target, conveniently, is related to Gibbs. As Abby says "If it seems like someone is out to get you, they are." The episode ends with Abby pleading with Gibbs for him to still love her regardless of what she does. Gibbs doesn't answer, but I think it's safe to assume he'll still love her.
The case took a backseat even though it's premise was interesting. I hope there is another serial killer case later on, because the story had great potential on its own. A Marine is found with his feet cut off and later, more feet are found. It turns out that the Marine was a hitman for the Reynosa Cartel cut off feet as proof. Claudia Black's character is the one who killed him after she was drugged and cut off his feet to make it seem like the same serial killer.
Abby is faced with an incredibly hard decision and doesn't have much wriggle room. Gibbs, too, can't do much unless he actively stops Abby which is against his nature.
Score: 9.3/10