Monday on Gossip Girl, Serena and Charlie go undercover to determine why Dan and Blair are spending so much time together, giving S' cousin a true taste of UES life.

Meanwhile, Raina decides to go on a search for her mother, which rankles Chuck, whose concerns about his own history run rampant as he worries what she'll find.

Gossip Girl producers Amanda Lasher and Joshua Safran preview both these story lines in the featurette below, which also shows some new clips from the episode.

Watch their take on "Petty in Pink" and see what you think:

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