The crew of the USS Nathan James are stationed in the Arctic with two civilian virologists searching for the source of a deadly virus.
Chandler and his crew head to Guantanamo Bay in hopes of collecting food, medical supplies and fuel, but they come under attack by escaped Gitmo prisoners.
The James faces off against a new foe who demands Chandler hand over Rachel and her research.
Chandler and his crew are put under extreme duress when the ship suffers a catastrophic event and Dr. Scott is in danger of losing all her research on the virus.
Chandler and Slattery lead a small team into the jungles of Nicaragua on a mission to find monkeys for vaccine trials, but instead run across a former drug kingpin.
Panic spreads throughout the ship when Lt. Danny Green comes down with a mysterious illness that could be the virus.
After picking up a distress call, Chandler and a small team stage a rescue, but a surprise attack leaves Chandler and Tex stranded at sea.
Slattery must act as commanding officer to save Chandler.
Rachel & Chandler ask for volunteers to test her vaccine.
Chandler and his crew finally return home in the season finale, but he discovers something absolutely terrifying about this brave new world.