 Jack takes drastic measures to ensure that the NSC never finds out the truth about Sydney s murder of the Russian diplomat Lazenzy. But his actions place a heavy strain on Vaughn s marriage, as Lauren gets closer and closer to the truth about Sydney. Meanwhile, Sydney agrees to go on a mission with Sloane in order to thwart plans to obtain the operating system to a deadly weapon, and she discovers an unlikely ally in the hunt for her missing two years.