The sky erupts. Cities darken, food spoils and homes fall silent. Civilization collapses.
End-of-the-world novel? A video game? Or could such a scenario loom in America's future?
There is talk of catastrophe ahead, depending on whom you believe, because of the threat of an electromagnetic pulse triggered by either a supersized solar storm or terrorist A-bomb, both capable of disabling the electric grid that powers modern life.
Electromagnetic pulses (EMP) are oversized outbursts of atmospheric electricity. Whether powered by geomagnetic storms or by nuclear blasts, their resultant intense magnetic fields can induce ground currents strong enough to burn out power lines and electrical equipment across state lines.
The threat has even become political fodder, drawing warnings from former House speaker Newt Gingrich, a likely presidential contender.
"We are not today hardened against this," he told a Heritage Foundation audience last year. "It is an enormous catastrophic threat."
Meanwhile, in Congress, a "Grid Act" bill aimed at the threat awaits Senate action, having passed in the House of Representatives.
Fear is evident. With the sun's 11-year solar cycle ramping up for its stormy maximum in 2012, and nuclear concerns swirling about Iran and North Korea, a drumbeat of reports and blue-ribbon panels center on electromagnetic pulse scenarios.
"We're taking this seriously," says Ed Legge of the Edison Electric Institute in Washington, which represents utilities. He points to a North American Electric Reliability Corp. (NERC) report in June.