Blair (Leighton Meester) does not approve of the new man, Cyrus Rose (guest star Wallace Shawn), in her mother's (guest star Margaret Colin) life, so she makes it her mission to break up the lovebirds by any means necessary. Jenny (Taylor Momsen) moves in with Agnes (guest star Willa Holland) as the friends move forward with their plans for a fashion line. Serena (Blake Lively) continues to fall for the new guy in her life, Aaron (guest star John Patrick Amedori), but she learns something about him that threatens to end things just as they are getting really good. Dan (Penn Badgley) decides to win the trust of Bart Bass (guest star Robert John Burke) in order to learn more about the man and possibly write an expose on him for Vanity Fair, but things get heated after Chuck (Ed Westwick) finds out the real reason Dan is spending so much time around his family.