Forced with the prospect of getting his hotel back, he goes behind Blair's back to trick her into sleeping with his uncle in such a way that he need not ask her upfront.
At first, Blair was repulsed at the very idea (although Jack reminded her it's not completely without precedent).
But after witnessing Chuck snap back at her, she reconsidered and actually fell for it; which is horrible because it also showed how deeply she cared for Chuck.
Serena's grand plan to show Nate her appreciation on his birthday was to make it seem like she doesn't give a crap then surprise him with an assassin-themed party.
This fit right into Jenny's not-so-hidden plan to steal Nate.
Eric quickly realized what she was up to. After witnessing Dorota's engagement, he espied Jenny running after Nate.
He also happened to drop his assassin game photo, which would be instrumental in him meeting his new love interest Elliot.
After planting a little kiss on Nate during the end of the game, Little J seemed to have realized the error of her ways and surrendered.
Meanwhile, Dan and Vanessa struggled with honesty issues. Neither wants to be critical now that they're a couple. But while they agreed to be more honest going forward, Dan still doesn't know she applied to the same program as he.
(Source: TV Fanatic)