"How could he do it?" Rhyme asked. "I thought he used the substation yesterday because it was too dangerous to splice into a main line."

"True, but, I don't know, maybe he's developed some kind of remote switchgear to let him rig a splice, then activate it later."

McDaniel asked, "Any idea where?"

"The line I'm thinking of is about three-quarters of a mile long. It runs under Central and West Harlem to the river."

"And you absolutely can't shut it down?"

"Not until the switchgear's repaired in the burned substation. That'll take a few hours."

"And this arc flash could be as bad as yesterday's?" Rhyme asked.

"At least. Yes."

"Okay, we'll check it out."

"Detective Rhyme? Tucker?" Her voice was less brittle than earlier.

It was the FBI agent who said, "Yes?"

"I'm sorry. I think I was being difficult yesterday. But I honestly didn't believe that one of my employees would do this."

"I understand," McDaniel said. "At least we've got the name now. If we're lucky we'll stop him before more people get hurt."

As they disconnected, Rhyme was shouting, "Mel, you get that? Uptown? Morningside Heights, Harlem. Museum, sculptor, whatever. Now, find me a possible target!" Rhyme then called the temporary head of the Crime Scene Unit in Queens-the man with his former job-and asked him to send a team to the substation closed because of the arson. "And have them bring back whatever they find, stat!"

"Got a possibility!" Cooper called, tilting his head away from the phone. "Columbia University. One of the biggest lava and igneous rock collections in the country."

Rhyme turned to Sachs. She nodded. "I can be there in ten minutes."

They were both glancing at the digital clock on Rhyme's computer screen.

The time was 11:29.

AMELIA SACHS WAS on the Columbia University campus, Morningside Heights, in northern Manhattan.

She had just left the Earth and Environmental Science Department office, where a helpful receptionist had said, "We don't have a volcano exhibit, as such, but we have hundreds of samples of volcanic ash, lava and other igneous rock. Whenever some undergrads come back from a field project, there's dust all over the place."

"I'm here, Rhyme," she said into the mike and told him what she'd learned about the volcanic ash.

He was saying, "I've been talking to Andi Jessen again. The transmission line goes underground basically all the way from Fifth Avenue to the Hudson. It roughly follows a Hundred and Sixteen Street. But the lava dust means the arc is rigged somewhere near the campus. What's around there, Sachs?"

"Just classrooms, mostly. Administration."

"The target could be any of them."

Sachs was looking from right to left. A clear, cool spring day, students meandering or jogging. Sitting on the grass, the library steps. "I don't see a lot of likely targets, though, Rhyme. The school's old, mostly stone and wood, it looks like. No steel or wires or anything like that. I don't know how he could rig a large trap here to hurt a significant number of people."

Then Rhyme asked, "Which way is the wind blowing?"

Sachs considered this. "To the east and northeast, it looks like."

"Logically, what would you think? Dust wouldn't blow that far. Maybe a few blocks."

"I'd think. That'd put him in Morningside Park."

Rhyme told her, "I'll call Andi Jessen or somebody at Algonquin and find out where the transmission lines are under the park. And, Sachs?"

"What?"

He hesitated. She guessed-no, knew-that he was going to tell her to be careful. But that was an unnecessary comment.

"Nothing," he said.

And disconnected abruptly.

Amelia Sachs walked out one of the main gates in the direction the wind was blowing. She crossed Amsterdam and headed down a street in Morningside Heights east of the campus, toward dun-shaded apartments and dark row houses, solidly built of granite and brick.

When her phone trilled she glanced at caller ID. "Rhyme. What do you have?"

"I just talked to Andi. She said the transmission line jogs north around a Hundred Seventeenth then runs west under the park."

"I'm just about there, Rhyme. I don't see… oh, no."

"What, Sachs?"

Ahead of her was Morningside Park, filled with people as the hour approached lunchtime. Children, nannies, businesspeople, Columbia students, musicians… hundreds of them, just hanging out, enjoying the beautiful day. People on the sidewalks too. But the number of targets was only part of what dismayed Sachs.

"Rhyme, the whole west side of the park, Morningside Drive?"

"What?"

"They're doing construction. Replacing water mains. They're big iron pipes. God, if he's rigged the line to them…"

Rhyme said, "Then the flash could hit anywhere on the street. Hell, it could even get inside any building, office, dorm, a store nearby… or maybe miles away."

"I've got to find where he connected it, Rhyme." She slipped her phone into its holster and jogged to the construction site.

SAM VETTER HAD mixed feelings about being in New York.

The sixty-eight-year-old had never been here before. He'd always wanted to make the trip from Scottsdale, where he'd lived for 100 percent of those years, and Ruth had always wanted to see the place, but their vacations found them in California or Hawaii or on cruises to Alaska.

Now, ironically, his first business trip after her death had brought him to New York, all expenses paid.

Happy to be here.

Sad Ruth couldn't be.

He was having lunch, sitting in the elegant, muted Battery Park Hotel dining room, chatting with a few of the other men who were here for the construction finance meeting, sipping a beer.

Businessman talk. Wall Street, team sports. Some individual sports talk too, but only golf. Nobody ever talked about tennis, which was Vetter's game. Sure, Federer, Nadal… but tennis wasn't a war story sport. The topic of women didn't much enter into the discussion; these men were all of an age.

Vetter looked around him, through the panoramic windows, and worked on his impression of New York because his secretary and associates back home would want to know what he thought. So far: really busy, really rich, really loud, really gray-even though the sky was cloudless. Like the sun knew that New Yorkers didn't have much use for light.

Mixed feelings…

Part of which was a little guilt about enjoying himself. He was going to see Wicked, to see if it stacked up to the Phoenix version, and probably Billy Elliott, to see if it stacked up to the trailers of the movie. He was going to have dinner in Chinatown with two of the bankers he'd met that morning, one based here and one from Santa Fe.

Maybe there was a hint of infidelity about the whole enjoyment thing.

Of course, Ruth wouldn't've minded.

But still.

Vetter also had to admit he was feeling a little out of his element here. His company did general construction, specializing in the basics: foundations, driveways, platforms, walkways, nothing sexy, but necessary and oh-so-profitable. His outfit was good, prompt and ethical… in a business where those qualities were not always fully unfurled. But it was small; the other companies that were part of the joint venture were bigger players. They were more savvy about business and regulatory and legislative matters than he was.

The conversation at the lunch table kept slipping from the Diamondbacks and the Mets to collateral, interest rates and high-tech systems that left Vetter confused. He found himself looking out the windows again at a large construction site next to the hotel, some big office building or apartment going up.