2x12 It's a Wonderful Lie

For the annual Snowflake Ball, Blair and Chuck make a bet that they can find the ideal dates for each other but end up dancing with one another in the end. Aaron’s ex-girlfriend, Lexi (guest star Natalie Knepp), expresses an interest in Dan which creates conflicted feelings for Serena. Nate, Jenny and Vanessa get into a tangled situation that puts their friendships and hearts on the line. Lily and Rufus also end up dancing with each other at the Ball, also. But all problems are put on hold when it is discovered that a loved one's life has been claimed.