After a pandemic outbreak, a mutated form of rabies results in most humans being turned into a highly intelligent new species known as "The Infected": a human survivor, Morgan (Matt Smith), with the ability to talk with the "infected," investigates these species and pursues "Patient Zero" to find an antidote to save humanity, including his infected wife. Aiding Morgan on the mission to find Patient Zero is CDC virologist Dr. Gina Rose (Natalie Dormer), leading the scientific research efforts, while Colonel Knox (Clive Standen) is in charge of the military front