Serena's jealousy, incredulity at B for not reciprocating Dan's love, and general lack of direction in life reach critical mass when she got a little too excited playing Dan's girlfriend again.
She sends in a page from B's diary to GG, exposing the fact that she may be hedging in reciprocating Dan's love. Just as B agreed to go to Italy with him, too. Crazy.
Meanwhile, Ivy (Kaylee DeFer) and Lola (guest star Ella Rae Peck) team up to help Chuck (Ed Westwick) with a personal vendetta, and entrap the businessman who sought to kill Bart.
They expose him, by nailing Andrew Tyler, and Bart is free to show his face again on the Upper East Side. He has yet to tell Lily about his return from the dead, however.
Nate (Chace Crawford) makes a decision about the future with Diana Payne (guest star Elizabeth Hurley). He decides to let her walk away and begin anew in London.
(Source: TV Fanatic)