From the depths of the Indian Ocean, a horrific plague has arisen to devastate humankind - a disease that's unknown, unstoppable... and deadly. But it is merely a harbinger of the doom that is to follow. Aboard a cruise liner transformed into a makeshift hospital, Dr. Lisa Cummings and Monk Kokkalis - operatives of SIGMA Force - search for answers to the bizarre affliction. But there are others with far less altruistic intentions. In a savage and sudden coup, terrorists hijack the vessel, turning a mercy ship into a floating bio-weapons lab.