Plot summary
Intelligence learns that the remaining militia members and their Al-Qaeda companions are attempting to cross into Israel by tunnel with the military drone and biological weapon. When watchers radio the terrorists that Israeli forces are blocking the tunnel exit, the Al-Queda members shoot the militia members and flee with the weapons. In Jerusalem, Henry interrogates the militia member who survived the shooting and learns that the new target might be in Rome. Elizabeth and Conrad are in Rome for a G-20 meeting. A drone is aimed at Vatican City but the Americans take control of it and crash it.
Bioweapons experts at the crash site say there is no evidence of a biological weapon, leading Elizabeth to conclude that the real target is the G-20 assemblage of leaders. Terrorists release the aerosolized weapon but the HVAC system is shut down and they are the only ones infected by the weapon. Stevie realizes that she does not want to go to Harvard. Blake tells Elizabeth that he is bisexual.
Credits
Adapted from Wikipedia contributors, Madam Secretary season 3. HTML formatting and reference markers removed.