After the horrifying revelations and reversals of fortune in Baltimore, Chandler and his fractured team join forces with an underground resistance in an attempt to defeat Amy Granderson. With doses of the cure running low, Rachel tries to do some good for the sick while remaining a prisoner at Avocet.
A global virus pandemic nearly obliterates the earth's population, forcing the crew of a naval destroyer to confront the reality of their new existence in a dangerous new world where they are among the only survivors. They must find a way to pull humanity from the brink of extinction.