Blair does not approve of the new man, Cyrus Rose, in her mother's life, so she makes it her mission to break up the lovebirds by any means necessary. Jenny moves in with Agnes as the friends move forward with their plans for a fashion line. Serena continues to fall for the new guy in her life, Aaron, but she learns something about him that threatens to end things just as they are getting really good. Dan decides to win the trust of Bart Bass in order to learn more about the man and possibly write an expose on him for Vanity Fair, but things get heated after Chuck finds out the real reason Dan is spending so much time around his family.
Title comes from the 1987 novel The Bonfire of the Vanities.