Gossip Girl (2.23): The Wrath of Con

The presumed dead lovechild of Lily and Rufus appears alive in need of his parents looking for help to finish his Senior Year of high school.

Airdate: May 4, 2009

Blair pressures Georgina into making amends for her past bad behavior by helping her in a scheme. The rivalry between Nate and Chuck over Blair comes to a head. Lily hatches a secret plan to help Rufus with Dan's college tuition. Blake Lively, Taylor Momsen and Jessica Szohr also star. Source: The CW

04/13 - The love child/never-meant-to-be will show up May 4 to wreak havoc on Lily and Rufus' blissful, excitement-free union. I'm hearing it's kind of cliff-hang-y. Source: TV Guide Online