Chuck offers to throw a wedding for a very pregnant Dorota who insists that she and Vanya have a traditional wedding before her parents arrive from Poland and find their daughter pregnant and without a husband. Dorota asks Blair and Chuck to be part of the ceremony and walk her down the aisle. Serena tells Nate she is having breakfast with the Humphreys when in reality she's secretly meeting up with Carter Baizen. Rufus discovers that Lily has been lying to him about her whereabouts. In this episode, Leighton Meester's song "Your Love is a Drug" is featured.
Title comes from the 1988 novel The Unbearable Lightness of Being.