That sound you hear is of it being ON.

Old habits die hard on the Upper East Side, and old feuds die even harder. Eva is right that Chuck and Blair have a certain magnetism. The problem is that it's led to all-out sabotage.

We're torn on "Touch of Eva" because, like Georgina a week earlier, the titular character up and left rather abruptly. That's it? After all she and Chuck have been through this summer?

If she stuck by him after hearing his secrets (that must've been some talk) and he by her despite her prostitution (!?) past, this seemed like a weak straw to break the camel's back.

GONE FOR-EVA: Blair forced out Chuck's lady love. But what comes next?

Then again, well ... it's so ON now! Those clamoring for a Chair reunion down the line have seen the last of Eva, at least, and those who love a good war won't be disappointed.

A couple of problems with this episode, though:

1. Why does Blair can still care so much in the first place about someone who traded her to his uncle Jack for a hotel? Or who slept with Jenny Humphrey?
2. If she does care that much, as evidenced by her plea for his return in "Double Identity" (one of our all-time favorite scenes), why behave like this now?
3. Would a master manipulator such as B really think the passport lie wouldn't come back to bite her? Was she so spiteful she just didn't care if it did?

These questions leave us a little confused as to the continuity of the season and its characters, but hey, it'll be fun now. Welcome back, Chuck of old. Whose side are you on?

Elsewhere, it appears that the waffling Serena has pushed both Dan and Nate over the edge. The former found this out first hand by pseudo cheating on Vanessa last night.

We're calling it that, anyway. To lie your whereabouts to their live-in lover, while sneaking around with a hotter girl? That's like the middle-aged person version of cheating.

Dan gets caught in that lie by none other than Juliet, who suggests Vanessa confront Serena. She is relentless. At least the mystery of Juliet's meddling remains unsolved!

It looked like a Derena reunion was a done deal ... until he sees his fair maiden comforting Nate, who had just broken up with shady Juliet, and delivers a great kiss-off line:

"Serena, there are some people who don't need to choose." Burn.

EASY MARK: Juliet is playing Nate so hard. But to what end?

Danessa reunites with a declaration of love. He's happy to be with someone truly devoted to him, but will it last? Will the same lack of passion drive him away once more?

Nate's split with Juliet lasted about as long. Juliet calms his fears with the claim that Ben is her "troubled" brother who has ruined relationships in the past. A likely story.

Good enough for Nate, though! Rather than suspecting ... whatever she's actually up to, he was convinced she's stepping out on him. Now he seems reassured. Poor guy.

What do you think this girl is truly up to? Ben has to be the prisoner from last week's closing sequence, right? This looks to be building toward some epic UES showdown.

In the end, not the best Gossip Girl of all time. A little forced, a little uneven, and a little boring at times. But there were more than enough fireworks to keep us invested.

What did you think of the episode? Vote and comment below!

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