In the dead of night, the hulks of four 372-ft. cooling towers and two high domed nuclear reactor container buildings were scarcely discernible above the gentle waters of the Susquehanna River, eleven miles southeast of Harrisburg, Pa. Inside the brightly lit control room of Metropolitan Edison’s Unit 2, technicians on the lobster shift one night last week faced a tranquil, even boring watch. Suddenly, at 4 a.m., alarm lights blinked red on their instrument panels. A siren whooped a warning. In the understated jargon of the nuclear power industry, an “event” had occurred. In plain English, it was the beginning of the worst accident in the history of U.S. nuclear power production, and of a long, often confused nightmare that threw the future of the nuclear industry into question.