With doubt still surrounding the tragedy at the White House, Sterling encounters an unlikely ally in Simon, who risks his life to return with a possible antidote. Against the wishes of Chief of Staff Richard Peel, Jarvis authorizes an air strike to neutralize them.
Sophia continues on her plan to exterminate the human race, now with the help of an unwitting accomplice — Leila. Meanwhile Sean and Vicky try to prevent the deaths of many thousands of innocent people.
Episode Title = "One Will Live, One Will Die"