Underneath her feet she believed she could feel a rumbling like massive nineteenth-century engines groaning away. She heard a low hum.

She closed the car door and approached the main entrance. Two guards were watching her. They were clearly curious about the tall redhead, curious about her arrival in an old ruddy muscle car, but they also seemed amused at her reaction to the building. Their faces said, Yeah, it's really something, isn't it? After all these years here you never get over it.

Then, with her ID and shield flashed, their expressions became alert and-apparently expecting a cop, though not in this package-they ushered her immediately through the halls of what was the executive headquarters portion of Algonquin Consolidated.

Unlike the slick office building in Midtown of a massive data mining company involved in a case she'd recently worked, Algonquin seemed like a museum diorama of life in the 1950s: blond wood furniture, framed gaudy photographs of the facility and transmission towers, brown carpet. The clothing of the employees-nearly all of them men-was ultra-conservative: white shirts and dark suits.

They continued down the boring halls, decorated with pictures of magazines that featured articles about Algonquin. Power Age. Electricity Transmission Monthly. The Grid.

The time was nearly six-thirty and yet there were dozens of employees here, ties loosened, sleeves rolled up, faces troubled.

At the end of the corridor the guard delivered her to the office of A. R. Jessen. Although the drive here had been eventful-involving speeds close to seventy on one stretch of highway-Sachs had managed to do a bit of research. Jessen was not an Andy but an Andi, for Andrea. Sachs always made it a point to do homework like this, learn what she could about the principals. It was important in maintaining control of interviews and interrogations. Ron had assumed that the CEO was a man. She imagined how her credibility would have fallen had she arrived and asked for Mr. Jessen.

Inside, Sachs paused just inside the doorway of the anteoffice. A secretary, or personal assistant, in a tight black tank top and wearing bold high heels, rose on precarious toes to dig into a filing cabinet. The blonde, in her early forties or late thirties, Sachs reckoned, was frowning, frustrated at being unable to find something her boss wanted.

In the doorway to the main office stood an imposing woman with salt-and-pepper hair and wearing a severe brown suit and high-neck blouse. She frowned as she watched the file cabinet excavation and crossed her arms.

"I'm Detective Sachs, I called earlier," she said when the dour woman turned her way.

It was then that the younger woman plucked a folder from the cabinet and handed it to the older, then said, "I found it, Rachel. My mistake, I filed it when you were at lunch. If you could make five copies, I'd appreciate it."

"Yes, Ms. Jessen," she said. And stepped to a copier.

The CEO strode forward on the dangerous heels, looked up into Sachs's eyes and shook her hand firmly. "Come on inside, Detective," she said. "Looks like we have a lot to talk about."

Sachs glanced over at the brown-suited personal assistant and followed the real Andi Jessen into her office.

So much for homework, she reflected ruefully.

ANDREA JESSEN SEEMED to catch on to the near faux pas. "I'm the second youngest and the only woman head of a major power company in the country. Even with me having the final say on hiring, Algonquin has a tenth the women as in most other big companies in the United States. It's the nature of the industry."

Sachs was about to ask why Jessen had gone into the field when the CEO said, anticipating her, "My father was in the business."

The detective nearly told her that she was a cop exclusively because of her own father, a "portable," or foot patrolman, with the NYPD for many years. But she refrained.

Jessen's face was angular, with the slightest dusting of makeup. Wrinkles were present but subdued, radiating timidly from the corners of her green eyes and bland lips. Otherwise the skin was smooth. This was not a woman who got outside much.

She in turn examined Sachs closely, then nodded toward her large coffee table, surrounded by office chairs. The detective sat while Jessen grabbed the phone. "Excuse me for a moment." Her manicured but unpolished nails clacked against the number pad.

She called three different people-all about the attack. One, to a lawyer, the detective could tell, one to the public relations department or an outside PR firm. She spent most of the time on the third call, apparently making sure extra security personnel were on site at all the company's substations and other facilities. Jotting tiny notes with a gold-plated pencil, Jessen spoke in clipped tones, using staccato words with not a single filler like "I mean," or "you know." As Jessen rattled off instructions, Sachs took in the office, noting on the broad teak desk a picture of a teenage Andi Jessen and her family. She deduced from the series of photos of the children that Jessen had one brother, a few years younger. They resembled each other, though he was brown-haired and she blonde. Recent pictures showed him to be a handsome, fit man in an army uniform. There were other pictures of him on travels, occasionally with his arm around a pretty woman, different in every shot.

There were no pictures of Jessen with any romantic partners.

The walls were covered with bookcases and pictures of oldtime prints and maps that might have come out of a museum display about the history of power. One map was labeled The First Grid, and showed a portion of lower Manhattan around Pearl Street. She saw in legible script, Thomas A. Edison, and she guessed that was the inventor's actual signature.

Jessen hung up and sat forward, elbows on her desk, eyes bleary but jaw and narrow lips firm. "It's been over seven hours since the… incident. I was hoping you'd have somebody in custody. I guess if you'd caught them," she muttered, "I would've had a phone call. Not a visit in person."

"No, I'm here to ask you some questions about things that have come up in the investigation."

Again a careful appraisal. "I've been talking with the mayor and the governor and the head of the FBI's New York office. Oh, Homeland Security too. I was expecting to see one of them, not a police officer."

This wasn't a put-down, not intentionally, and Sachs took no offense. "NYPD is running the crime scene portion of the case. My questions have to do with that."

"That explains it." Her face softened slightly. "Woman to woman, I get a bit defensive. I was thinking the big boys weren't taking me seriously." A faintly conspiratorial smile. "It happens. More than you'd think."

"I understand that."

"I imagine you do. A detective, hm?"

"That's right." Then Sachs, feeling the urgency of the case, asked, "We get to those questions?"

"Of course."

The phone kept ringing, but according to Jessen's instructions to her PA, who'd returned to the anteoffice a moment ago, the unit chirped only once and fell silent as the woman fielded the calls.

"First of all, just a preliminary matter. Have you changed the access codes to the grid software?"

A frown. "Of course. That's the first thing we did. Didn't the mayor or Homeland Security tell you?"

No, they hadn't, Sachs reflected.

Jessen continued, "And we've put in an extra set of firewalls. The hackers can't get in any longer."

"It's probably not hackers."

Jessen cocked her head. "But this morning Tucker McDaniel was saying that it was probably terrorists. The FBI agent?"

"We have more recent information."

"How else could it have happened? Somebody from the outside was rerouting the supply and altering the circuit breakers at MH-Ten-the substation on Fifty-Seventh Street."