Alana Vaughn, an infectious diseases expert with NATO, is urgently summoned to Genoa by an ex-lover to examine a critically ill patient. She's stunned to discover that the illness is a recurrence of the Black Death. Alana soon suspects bioterrorism, but her WHO counterpart, Byron Menke, disagrees. In their desperate hunt to track down Patient Zero, they stumble across an 800-year-old monastery and a medieval journal that might hold the secret to the present-day outbreak. With the lethal disease spreading fast and no end in sight, it's a race against time to uncover the truth before millions die.