Set just before the start of the Armageddon, the series follows two central characters, a physicist and a nun, in a race against time to see if the end of the world can be averted. Bill Pullman portrays Dr. Richard Massey, a Harvard physics professor and father mourning the death of his daughter, who was murdered by an evil satanist with seemingly supernatural abilities. Natascha McElhone portrays a nun who appeals to Massey to help her investigate whether the apocalyptic prophecy from the Book of Revelations is starting to come true.