Philip and Elizabeth are given an urgent task to plant a bug in Defense Secretary Caspar Weinberger's office; Stan closes in on a member of the Soviet Rezidentura.
Philip and Elizabeth must stop an assassin from taking out key U.S. scientists; Grannie shocks Elizabeth with the truth of what happened between Philip and Irina in New York.
A mole hunt within the KGB causes suspicion amongst allies and shatters trust within the Jennings' marriage; Stan's plan to keep his mole safe puts her at even greater risk of discovery.
Philip and Elizabeth are put to the test when a routine mission goes horribly wrong; Stan and the FBI are pushed to their limit.
Philip and Elizabeth evacuate their children while trying to complete the mission; Stan holds Nina's future in his hands.