String and Caitlin travel to a deserted island where a cure is being researched for a biological plague that was developed in Afghanistan. Unfortunately, the plague has already gotten out of control and the researchers are all dead. Complicating matters, the Russians have also dispatched a submarine to the island to attempt to recover the cure first. When String, Caitlin and the sub's crew all get exposed to the virus, they must work together to find the cure before they all go mad and either kill one another or die.