Serena enlists Charlie to go undercover Gossip Girl-style to determine why Dan and Blair are spending so much time together, and what role an unexpected visitor is playing in their lives. Watch free, streaming full episodes of Gossip Girl on cwtv.com. Gossip Girl Video: Watch Gossip Girl full episodes, previews, clips, interviews and more video. Gossip Girl is based on the best-selling series of young-adult novels by Cecily von Ziegesar and executive produced by Josh Schwartz and Stephanie Savage. Gossip Girl is a drama based on the lives of privileged Manhattan prep school teens.