And finally Cleo. She hadn’t been on duty, but had decided that, as he was working, she might as well too.

Sometimes Roy found it hard to believe that he really was dating this goddess.

He watched her now, tall and leggy and almost impossibly beautiful in her green gown and white wellies, long blonde hair clipped up, moving around this room, her room, her domain, with such ease and grace, sensitive but at the same time impervious to all its horrors.

But all the time he was wondering if, in some terrible irony, he was witnessing the woman he loved laying out the remains of the woman he had once loved.

The room smelled strongly of disinfectant. It was furnished with two steel post-mortem tables, one fixed and the other, on which the remains of the woman now lay, on castors. There was a blue hydraulic hoist by a row of fridges with floor-to-ceiling doors. The walls were tiled in grey and a drainage gully ran all the way around. Along one wall was a row of sinks, with a coiled yellow hose. Along another were a wide work surface, a metal cutting board and a glass-fronted display cabinet filled with instruments, some packs of Duracell batteries and grisly souvenirs that no one else wanted – mostly pacemakers – removed from victims.

Next to the cabinet was a wall chart listing the name of the deceased, with columns for the weight of their brain, lungs, heart, liver, kidneys and spleen. All that was written on it so far was ‘ANON. WOMAN’.

It was a sizeable room but it felt crowded this afternoon, as it always did during a post-mortem by a Home Office pathologist.

‘There are four fillings,’ Christopher Ghent said, to no one in particular. ‘Three white composite and one gold inlay. An all-porcelain bridge from upper right six to four, not cheap. No amalgams. All high-quality stuff.’

Grace listened, trying to remember what dental work Sandy had had. She had been fastidious about her teeth. But the description was too technical for him.

Joan Major was unpacking, from a large case, a series of plaster of Paris models. They sat there on square black plastic plinths like broken archaeological fragments from an important dig. He had seen them before, but he always found it hard to get his head around the subtle differences they illustrated.

When Christopher Ghent finished reciting his dental analysis, Joan began to explain how each model showed the comparison of different stages of bone development. She concluded by stating that the remains were female, around thirty years old, give or take three years.

Which continued to cover the age Sandy had been when she disappeared.

He knew he should put that from his mind, that it was unprofessional to be influenced by any personal agenda. But how could he?

The floor was shaking. Key blanks, dozens of them hanging in rows on hooks along one wall of the store, were clinking. Several cans of paint fell from a shelf. The lid came off one as it hit the floor and magnolia emulsion poured out. A cardboard box tumbled, sending brass screws wriggling like maggots across the linoleum.

It was dark in the deep, narrow hardware store just a few hundred yards from the World Trade Center, where Ronnie had taken refuge, following the tall cop in here. Some minutes earlier the power had gone off. Just one battery-powered emergency light was on. A raging dust tornado twisted past the window, blacker some moments than night.

A shoeless woman in an expensive suit, who didn’t look like she had been in a hardware store before in her life, was sobbing. A gaunt figure in brown overalls, grey hair bunched in a ponytail, stood behind the counter that ran the full length down one side, presiding over the gloom in grim, helpless silence.

Ronnie still held tightly on to the handle of his suitcase. Miraculously, his briefcase was still resting on top.

Outside, a police car spun past on its roof, like a top, and stopped. Its doors were open and its dome light was on. The interior was empty, a radio mike dangling from its twisted cord.

A crack suddenly appeared in the wall to his left and an entire stack of shelves, laden with boxes of different-sized paintbrushes, crashed to the floor. The sobbing woman screamed.

Ronnie took a step back, pressing against the counter, thinking. He had been in a restaurant in Los Angeles once during a minor quake. His companion then had told him the doorway was the strongest structure. If the building came down, your best chance of survival was to be in the doorway.

He moved towards the door.

The cop said, ‘I wouldn’t go out right now, buddy.’

Then a massive avalanche of masonry and glass and rubble came down right in front of the window, burying the cop car. The store’s burglar alarm went off, a piercing banshee howl. The ponytailed guy disappeared for a moment and the sound stopped, as did the clinking of the keys.

The floor wasn’t shaking any more.

There was a very long silence. Outside, quite quickly, the dust storm began to lighten. As if dawn was breaking.

Ronnie opened the door.

‘I wouldn’t go out there – know what I’m saying?’ the cop repeated.

Ronnie looked at him, hesitating. Then he pushed the door open and stepped out, towing his bag behind him.

Stepped out into total silence. The silence of a dawn snowfall. Grey snow lay everywhere.

Grey silence.

Then he started to hear the sounds. Fire alarms. Burglar alarms. Car alarms. Human screams. Emergency vehicle sirens. Helicopters.

Grey figures stumbling silently past him. An endless line of women and men with hollow, blank faces. Some walking, some running. Some stabbing buttons on phones. He followed them.

Stumbling blindly through the grey fog that stung his eyes and choked his mouth and nostrils.

He just followed them. Towing his bag. Following. Keeping pace. The girders of a bridge rose on either side of him. The Brooklyn Bridge, he thought it was, from his scant knowledge of New York. Running, stumbling, across the river. Across an endless bridge through an endless swirling, choking grey hell.

Ronnie lost track of time. Lost track of direction. Just followed the grey ghosts. Suddenly, for one fleeting instant, he smelled the tang of salt, then the burning smells again – aviation fuel, paint, rubber. At any moment there might be another plane.

The reality of what had happened was starting to hit him.

Hopefully Donald Hatcook was OK. But what if he wasn’t? The business plan he had created was awesome. They stood to make millions in the next five years. Fucking millions! But if Donald was dead, what then?

There were silhouettes in the distance. Jagged high-rise silhouettes. Brooklyn. He had never been to Brooklyn before in his life, just seen it across the river. It was getting nearer with every step forward. The air was getting better too. More prolonged patches of salty sea air. Thinning mist.

And suddenly he was going down an incline towards the far end of the bridge. He stopped and turned back. Something biblical came into his mind, some memory about Lot’s wife. Turning her head. Becoming a pillar of salt. That’s what the endless line of people passing him looked like. Pillars of salt.

He held on to a metal railing with one hand and stared back. Sunlight dappled the water below him. A million brilliant specks of white dancing on the ripples. Then beyond it the whole of Manhattan looked as if it was on fire. The high-rises all partially shrouded in a pall of grey, brown, white and black smoke clouds billowing up into the deep blue sky.

He was shaking uncontrollably and badly needed to collect his thoughts. Fumbling in his pockets, he pulled out his Marlboros and lit one. He took four deep puffs in quick succession, but it didn’t taste good, not with all the stuff in his throat, and he dropped it into the water below, feeling giddy, his throat even drier.