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.

Chuck is still reeling from the discovery that his ex-girlfriend Jill was a Fulcrum agent and goes on a mission to take his mind of off his shock. Casey gets a shock of his own when he finds out that his sensei Ty Bennett (guest star Carl Lumbly), who taught him everything he knows, is now one of the most wanted rogue agents. While on the search for Bennett, it becomes clear that Casey may be too emotionally involved to continue with the mission.

Cameron's secret night life is revealed as she seeks knowledge in a library with a friend who shares her interests, while a Terminator sent back to a wrong point in time results in a drastic alteration of the time line. Meanwhile, John and Riley's relationship is beginning to blossom.

Michael must hold the team together after they are betrayed by Self. T-Bag gets a new partner who blackmails Gretchen into finding a buyer for Scylla. Self makes the feds think that Lincoln killed him and the feds go after the team.