'What's this about wind and cold?' I asked, staring at the back of Lucy's head.

'Twenty, gusting to twenty-five out of the west,' she sounded in my headset. 'And gonna get worse. You guys doing all right back there?'

'We're fine,' I said as I thought of Carrie's deranged letter again.

Lucy flew in blue ATF fatigues, a pair of Cebe sunglasses blacking out her eyes. She had grown her hair, and it gracefully curled to her shoulders and reminded me of red jarrah wood, polished and exotic, and nothing like my own short silver-blond strands. I imagined her light touch on the collective and cyclic as she worked anti-torque pedals to keep the helicopter in trim.

She had taken to flying like everything else she had ever tried. She had gotten her private and commercial ratings in the minimum required hours and next got her certificated flight instructor rating simply because it gave her joy to pass on her gifts to others.

I needed no announcement that we were reaching the end of our flight as we skimmed over woods littered with felled trees scattered haphazardly like Lincoln Logs. Dirt trails and lanes wound narrowly, and on the other side of gentle hills, gray clouds got vertical as they turned into vague columns of tired smoke left by an inferno that had killed. Kenneth Sparkes's farm was a shocking black pit, a scorched earth of smoldering carnage.

The fire had left its trail as it had slaughtered, and from the air I followed the devastation of splendid stone dwellings and stables and barn to wide charred swaths that had denuded the grounds. Fire trucks had rolled over sections of the white fence surrounding the property and had churned up acres of manicured grass. Miles in the distance were more pasture land and a narrow paved public road, then a Virginia Power substation, and farther off, more homes.

We invaded Sparkes's privileged Virginia farm at not quite eight A.M., landing far enough away from ruins that our rotor wash did not disturb them. Marino climbed out and went on without me as I waited for our pilots to brake the main rotor and turn off all switches.

'Thanks for the lift,' I said to Special Agent Jim Mowery, who had helped Lucy fly this day.

'She did the driving.'

He popped open the baggage door.

'I'll tie her down if you guys want to go on,' he added to my niece.

'Seems like you're getting the hang of that thing,' I lightly teased Lucy as we walked away.

'I limp along the best I can,' she said. 'Here, let me get one of those bags.'

She relieved me of my aluminum case, which did not seem to weigh much in her firm hand. We walked together, dressed alike, although I did not wear gun or portable radio. Our steel-reinforced boots were so battered they were peeling and almost gray. Black mud sucked at our soles as we drew closer to the gray inflatable tent that would be our command post for the next few days. Parked next to it was the big white Pierce supertruck with Department of the Treasury seals and emergency lights, and ATF and EXPLOSIVES INVESTIGATION announced in vivid blue.

Lucy was a step ahead of me, her face shadowed by a dark blue cap. She had been transferred to Philadelphia, and would be moving from D.C. soon, and the thought made me feel old and used up. She was grown. She was as accomplished as I had been at her age, and I did not want her moving farther away. But I had not told her.

'This one's pretty bad.' She initiated the conversation. 'At least the basement is ground level, but there's only one door. So most of the water's in a pool down there. We got a truck on the way with pumps.'

'How deep?'

I thought of thousands of gallons of water from fire hoses and imagined a cold black soup thick with dangerous debris.

'Depends on where you're stepping. If I were you, I wouldn't have taken this call,' she said in a way that made me feel unwanted.

'Yes, you would have,' I said, hurt.

Lucy had made little effort to hide her feelings about working cases with me. She wasn't rude, but often acted as if she barely knew me when she was with her colleagues. I remembered earlier years when I would visit her at UVA and she did not want students to see us together. I knew she was not ashamed of me but perceived me as an overwhelming shadow that I had worked very hard not to cast over her life.

'Have you finished packing?' I asked her with an ease that was not true.

'Please don't remind me,' she said.

'But you still want to go.'

'Of course. It's a great opportunity.'

'Yes, it is, and I am so pleased for you,' I said. 'How's Janet? I know this must be hard…'

'It's not like we'll be in different hemispheres,' Lucy answered back.

I knew better, and so did she. Janet was an FBI agent. The two of them had been lovers since their early training days at Quantico. Now they worked for different federal law enforcement agencies and soon would live in separate cities. It was quite possible their careers would never permit their relationship again.

'Do you suppose we can carve out a minute to talk today?' I spoke again as we picked our way around puddles.

'Sure. When we finish up here, we'll have a beer, if we can find an open bar out here in the sticks,' she replied as the wind blew harder.

'I don't care how late it is,' I added.

'Here goes,' Lucy muttered with a sigh as we approached the tent. 'Hey gang,' she called out. 'Where's the party?'

'You're looking at it.'

'Doc, you making house calls these days?'

'Naw, she's babysitting Lucy.'

In addition to Marino and me, NRT on this call-out were nine men, two women, including team leader McGovern. All of us were dressed alike in the familiar dark blue fatigues, which were worn and patched and supple like our boots. Agents were restless and boisterous around the back of the open tailgate of the supertruck with its shiny aluminum interior divided into shelves and jump seats, and its outside compartments packed with reels of yellow crime-scene tape, and dustpans, picks, floodlights, whisk brooms, wrecking bars, and chop saws.

Our mobile headquarters was also equipped with computers, a photocopier and fax machine, and the hydraulic spreader, ram, hammer, and cutter used to deconstruct a scene or save a human life. In fact, I could not think of much the truck did not have except, perhaps, a chef, and more importantly, a toilet.

Some agents had begun decontaminating boots, rakes, and shovels in plastic tubs filled with soapy water. It was a never-ending effort, and in brisk weather, hands and feet never dried or thawed. Even exhaust pipes were swabbed for petroleum residues, and all power tools were run by electricity or hydraulic fluid instead of gasoline, preparing for that day in court when all would be questioned and judged.

McGovern was sitting on a table inside the tent, her boots unzipped, and a clipboard on her knee.

'All right,' she addressed her team. 'We've been through most of this already at the fire station, where you guys missed good coffee and donuts,' she added for the benefit of those of us who had just gotten here. 'But listen up again. What we know so far is the fire is believed to have started day before yesterday, on the evening of the seventh at twenty hundred hours.'

McGovern was about my age and based in the Philadelphia field office. I looked at her and saw Lucy's new mentor, and I felt a stiffening in my bones.

'At least that's the time the fire alarm went off in the house,' McGovern went on. 'When the fire department got here, the house was fully involved. Stables were burning. Trucks really couldn't get close enough to do anything but surround and drown. Or at least make an attempt at it. We're estimating about thirty thousand gallons of water in the basement. That's about six hours total to pump all of it out, assuming we're talking about four pumps going and don't have millions of clogs. And by the way, the power's off, and our local friendly fire department is going to set up lights inside.'