Gossip Girl - Season 5 - Eps 21: Despicable B
Blair feels like her Upper East Side status might be slipping away and devises a plan to assure that doesn’t happen. Meanwhile, Lily throws a family gathering – including William, Carol and Lola – in an attempt to prove the van der Woodsen family is as united as ever. Finally, Nate digs into Diana’s past and is surprised by what he discovers.
About Gossip Girl

Title: Gossip Girl
First Air Date: 2007-09-19
Last Air Date: 2012-12-17
Status: Ended
Rating: 8.199/10 (from 2163 votes)
Language: EN
Seasons: 7
Total Episodes: 121
Network: The CW
Genres: Drama, Mystery
Production Companies: Warner Bros. Television, Alloy Entertainment, Fake Empire Productions, CBS Studios
Synopsis
An exclusive group of privileged teens from a posh prep school on Manhattan's Upper East Side whose lives revolve around the blog of the all-knowing albeit ultra-secretive Gossip Girl.
Cast

Blake Lively
Serena van der Woodsen

Leighton Meester
Blair Waldorf

Penn Badgley
Dan Humphrey

Chace Crawford
Nate Archibald

Ed Westwick
Chuck Bass

Kaylee DeFer
Ivy Dickens

Kelly Rutherford
Lily van der Woodsen

Matthew Settle
Rufus Humphrey