After picking up a distress call near Jamaica, Chandler and a small team stage a rescue attempt. But a surprise attack leaves Chandler and Tex stranded at sea. Slattery and the crew search desperately to find their lost at sea Captain and his comrade, hoping to do so before their enemies beat them to it.

Rachel and Chandler ask for six volunteers to participate in human trials of her vaccine, but the tests could be a living hell as the virus and the vaccine do battle inside their bodies. Meanwhile back in the States, Chandler's wife and father are doing everything they can to keep their family alive.