Gossip Girl's April 25 episode promises to be a crucial one.

The show returns next week (April 18) with "The Kids Stay in the Picture." The following week, in "Petty in Pink," Serena enlists Charlie to go undercover, Gossip Girl style to determine why Dan and Blair are spending so much time together.

Meanwhile, with Nate’s help, Raina embarks on a search for her long-lost mom, and Chuck’s hopes about his legacy are dashed by devastating information from the past.

Click to enlarge photos from "Petty in Pink" below ...

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