Capt. Tom Chandler and his crew set out for the Arctic with two virologists and 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.

A ground mission to Guantanamo Bay takes a turn for the worse when Chandler and his comrades are attacked by escaped prisoners.

An enemy demands that Chandler hand over Rachel and her research and Chandler engages in a series of risky strategic moves.

The ship's propulsion system suffers a catastrophic event and Chandler's leadership and ingenuity are put to the test.

A small team heads to the jungles of Nicaragua to find monkeys for Rachel's vaccine trials and Chandler and his men face a moral dilemma when they encounter a former drug kingpin.

Panic spreads throughout the ship when Lt. Danny Green comes down with a mysterious illness. Also, Chandler begins to lose faith in Rachel's vaccine trials.