Captain America and Iron Man: two cornerstones of the Avengers, the world's most powerful super hero team. They've fought side by side, stopped deadly threats to the entire planet, and become close friends. No more. A tragic super human battle blows a hole straight through the center of Stamford, Connecticut, killing hundreds of people. The U.S. government responds swiftly, demanding that all super heroes--and villains--unmask and register their powers....