

At the Snowflake dance, Blair and Chuck discover their lookalikes hooking up. Aaron's ex Lexi flirts with Dan, causing trouble with Serena. Nate, Jenny and Vanessa get into a messy love triangle that involves a stolen letter and a revealing dress. Bart Bass suffers a car accident on his way to the ball.
As the summer draws to a close in the Hamptons, Serena and Nate have everyone fooled into thinking they are a couple to cover up the fact that Nate has been hooking up with a married, older woman. Blair returns from abroad with a hot guy on her arm, making a very jealous Chuck question his decision to leave Blair stranded at the heliport. Dan has spent the summer assisting a famous author. While interning for Eleanor Waldorf's company, Jenny sneaks an invite to a much-coveted Hamptons' White Party at which Eric introduces her to socialite Tinsley Mortimer.