“I don’t know,” one of his assistants said slowly. “But I’d think it’d have to be. Diagnostics say there’s no physical problem with the lines or switchgear.”

The supervisor stared at the screen, waited for the next logical step: letting them know which new substation-or stations-would kick in to fill the gap created by the loss of NJ-18.

But no such message appeared.

The three Manhattan substations, 17, 10 and 13, continued alone in providing juice to two service areas of the city that would otherwise be dark. The SCADA program wasn’t doing what it should have: bringing in power from other stations to help. Now the amount of electricity flowing into and out of each of those three stations was growing dramatically.

The supervisor rubbed his beard and, after waiting, futilely, for another substation to come online, ordered his senior assistant, “Manually move supply from Q-Fourteen into the eastern service area of MH-Twelve.”

“Yessir.”

After a moment the supervisor snapped, “No, now.”

“Hm. I’m trying.”

“Trying. What do you mean, trying?” The task involved simple keyboard strokes.

“The switchgear’s not responding.”

“Impossible!” The supervisor walked down several short steps to the technician’s computer. He typed commands he knew in his sleep.

Nothing.

The voltage indicators were at the end of the green. Yellow loomed.

“This isn’t good,” somebody muttered. “This’s a problem.”

The supervisor ran back to his desk and dropped into his chair. His granola bar and Greek athlete cup fell to the floor.

And then another domino fell. A third red dot, like a bull’s-eye on a target, began to throb, and in its aloof manner the SCADA computer reported: