A prisoner on death row in Idaho, soon to be executed, arranges to send remote killing devices to kill more people; the first to a San Francisco office building. Simone is sent to talk to the prisoner to find out more info.
It's a race against time as the Feds band together to stop death row inmate Foster and his cult following's killing spree ahead of his execution. Meanwhile, as Cutty and Ruth's relationship gets serious, Simone and Dina are forced to reconnect.