An Army ambulance sped by. No siren, only a dome on its roof flashing red. It halted in front of the high-security Tech Area, where several men wearing silver coveralls and carrying glistening instruments rushed out. Dr. Orr and Oppenheimer walked quickly toward a rolling gurney that held a man half wrapped in an aluminum body bag. The man was shaking.

Something bad had happened. Very bad. For a moment Stephen believed he was back in London. He was on the roof again, and there were bombs falling...