Capt. Tom Chandler and his crew set out for the Arctic with two virologists; Chandler discovers that the virologists are collecting samples of the source of a virus that has wiped out more than half of the human population while he has been at sea.
Chandler and his crew head to the U.S. military base in Guantanamo Bay in search of food, medical supplies and fuel; escaped prisoners attack the search teams; the teams enlist the help of a private contractor.
Slattery must step into the role of commanding officer; Slattery must find a way to get his people back without losing the vaccine prototype.
Chandler and his crew return home; a warlord threatens the restoration of law and order; Chandler sets out to save his family.
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.