S2, E5: The espionage life is beginning to take its toll on Chuck and everyone is noticing. Chuck tries to explain his unusual behavior to Ellie and to the quirky Buy More efficiency expert Emmett Milbarge (guest star Tony Hale - "Arrested Development," "Stranger than Fiction"), but a new assignment only complicates things. After a global terrorist comes searching for Jeff, Chuck is forced to socialize with Jeff in order to find out what role the oddball plays in the mission. Sarah, Casey and Chuck are all shocked when they discover that the fate of the world and the prevention of World War III rest in Jeff's hands.