Blake Lively, Leighton Meester, Penn Badgley, Chace Crawford, Ed Westwick, Kaylee DeFer, Kelly Rutherford, Matthew Settle

: It is revealed that William is the biological father of Lola Rhodes, the "real" Charlie Rhodes, making Serena and Lola half-sisters.

You can find more detailed summaries and fan reviews on the Gossip Girl Wiki or the Rotten Tomatoes episode page.

" Con Heir " is the 18th episode of the fifth season of the television series , which originally aired on April 2, 2012.