Soon, others exhibit the same mysterious symptoms: hacking coughs and fever, followed by seizure, brain hemorrhage…and ultimately, death. In Minneapolis, Chicago, London, Paris, Tokyo and Hong Kong, the numbers quickly multiply: one case becomes four, then sixteen, then hundreds, thousands, as the contagion sweeps across all borders, fueled by the countless human interactions that make up the course of an average day.

A global pandemic explodes.

At the U.S. Centers for Disease Control and Prevention, researchers mobilize to break the code of a unique biological pathogen as it continues to mutate. Deputy Director Cheever (Laurence Fishburne) tries to allay the growing panic despite his own personal concerns, and must send a brave young doctor (Kate Winslet) into harm's way. At the same time, amid a rising tide of suspicion over a potential vaccine—and who gets it first—Dr. Leonora Orantes (Marion Cotillard) of the World Health Organization works through the network of connections that could lead back to the source of what they're dealing with.