The Best Episodes Written By Leyani Diaz

Martinez and his Chief of Staff order their intelligence departments to determine the nature of Thomas' message and who it was sent to. Meanwhile, Thomas launches a surprise attack, Alaskan Senator Catherine Lewis threatens to go on national television to alert the public to the enemy among them, and Sean and Leila get a fresh lead on Samantha's location.

President Martinez makes a triumphant albeit shaky return to the White House, determined to punish the traitors who conspired against him. Sophia forges ahead with her plan, while battling a new enemy -- the guilt that has begun to plague her. Sean and Vicky form an impromptu team with Sterling and Simon in order to track down Sophia's headquarters and stop her before the destruction of all human life.