One thing, there was no going back. There never bloody was; his character flaw.

His guido put him seven hundred metres out from the city's easterly shore, height one hundred and fifty metres. Closing fast. Fog split around the leading edge of the wing, re-forming instantly behind the trailing edge. A slick coating of minute droplets was deposited on the leathery membrane, streaming backwards and shaking free in a horizontal rain.

The photon amp was boosted up to its highest resolution.

He still couldn't see anything.

"Virtual overlay," he told the guido 'ware. Translucent green and blue and red petals flipped up into the retinal feed from the photon amp. He looked out across a city built from frozen laserlight.

Morgan's people had built the virtual simulation up from the afternoon's satellite passes. Accurate to ten centimetres, more comprehensive than any memory in the city council's planning office data cores.

A flood of neutral pixels darkened and hardened below him, resolving into a solid black plane. He felt the illusion of space opening up around him again. Tremendously reassuring.

He just prayed that the simulation's alignment was correct. The shoreline buildings of the Gunthorpe district formed a flat abrupt wall of dimensionless green dead ahead. It was the only eastern district to expand since the Warming; a quirk of fate had placed it alongside a low triangular promontory jutting a couple of kilometres out into the basin. The fields and pastures which had survived the deluge had been swiftly covered in blocks of flats.

Two hundred metres off the promontory's tip was a patch of spiky indigo waveforms, as though an iceberg had endured the Warming and sought shelter in the basin. It was Eye, a village still in the process of being subsumed by the sluggish currents of the mire, reduced to an erratic formation of mud dunes and crumbling brick walls.

The guido 'ware printed a trajectory graphic for him. A tunnel of slender orange rings snaking away from him, round the north side of the urbanized promontory, and curving down to touch Walton.

Greg swung himself to one side, lining up the ghost wing in the centre of the tunnel. Orange rings flashed past silently.

Morgan had wanted to send one of his security division hardliners along on the penetration mission. Greg turned him down politely, hoping he wouldn't make an issue of it. They were tough and well trained, but there was a world of difference between corporate clashes and all-out combat. He needed someone he could rely on totally.

Back in Turkey, Greg had been in charge of a tactical raider squad when they were cut off and pinned down in a mountain village by Legion fire. Half of the men had wanted to make a break for it, but Greg made them stay put. Teddy was in charge of the back-up team.

He had spent the next three hours cowering under a dusty sky as bullets thudded into the sandstone walls of dilapidated hovels, and mortar rounds fell all around. Time had stretched out excruciatingly, but he never let go of that tenuous trust in his huge sergeant.

Teddy had eventually turned up in their ageing Belgian Air Force Black Hawk support helicopter, flown by a shaken, terrified pilot. Greg didn't learn until much later how Teddy persuaded the man to fly into the heart of a grade three fire zone. There would have been a court martial, except the pilot refused to testify.

Eleanor's right, I do dwell on Turkey too much.

But he was bloody glad it was Teddy in the second ghost wing.

The orange circles took him round the north of Gunthorpe. Here the basin mud had surged along a slight depression between Walton and Werrington, engulfing roads and buildings. It was only a metre deep, but the relentless pressure eroded bricks and concrete, exploiting every crack and crevice.

Foundations were eaten away, day by day, year by year, cement pulverized, reinforcement prongs corroded, bricks sucked out. Roofs had collapsed, the abraded walls sagged then fell. Even now the piles of rubble were still being assaulted from below, dragged down by the unstable alluvial substratum, a pressure that wouldn't end until the entire zone was levelled. Weeds and reeds choked the rolling mounds in a mouldy mat of entwined tendrils. The satellite image had shown the whole area crisscrossed by paths worn by adventurous children, glimmers of metal detritus peeking through the limp foliage.

The virtual simulation had shaded it in as a lightly nicked pink desert.

One hundred metres in altitude; and five hundred metres up ahead the tunnel of rings had dipped down at a steep angle, narrowing like a whirlwind to touch the apex of an old factory warehouse.

Greg dimmed the simulation, reducing it to a geometric lithograph. He banked the Westland to starboard, preparing to overfly the warehouse roof. The tunnel twisted into an impossible helix. He throttled back the propeller speed to idle, and glided in.

At last he thought he saw something through the scudding fog. Down below, a pale blur, broken by dark irregular smudges. According to the simulation he ought to be over the factory's yard. Big squares of cracked concrete with abandoned gutted lorries, a scattered cluster of railway van bogies in one corner.

With a bit of imagination the dark smudges below could be rusted cabs.

The simulated green skeletal outline of the warehouse was upon him. If it corresponded with the actual structure the Westland should take him six metres above the roof apex.

Solid surfaces suddenly materialized between the green lines, as if the building had been edged in neon tubes. Greg received a fast impression of breeze blocks smeared in rheumy ribbons of algae, and a corrugated roof, red oxide paint flaking away. He laughed as he twisted the throttle grip, shooting back up into the veil of fog.

"Morgan? Tell your programming team they've got a big drink coming. The guido virtual is perfect. I've just surveyed the landing site."

"Glad to hear it. Could you see anybody waiting?"

"No. It looks clear. I'm going around."

He made a leisurely turn, and headed back towards the warehouse. This time he came in lower. The orange tunnel stretched out ahead, perfectly level. It terminated halfway up the slope of the roof.

He saw the corrugated panels again, four seconds before he reached them. Legs running in mid-air. Then the rubber soles of his desert boots slapped down.

Every nerve was raw-edged with tension. If the panels couldn't take his weight he was in deep shit and no messing. The satellite image interpreters swore they would hold.

The noise of his running feet sounded like a drum beat after the graveyard silence of flight. He could feel the panels bending slightly under his heels. The apex was three metres ahead of him. Still the panels held.

He yanked savagely at the throttle grip, reversing the propeller pitch. Tilting the wing back up as he fought to kill his forward momentum. The sudden backward impetus nearly toppled him.

"Shitfire! Tell you, next time we do as Julia says and send in the cavalry."

"Greg?" Teddy called. "You down, boy?"

He was crouched a metre short of the apex, balancing the wing precariously. Fog swirled beyond the guttering, cutting off any view of the yard below.

"Yeah. Wait one."

He killed the virtual simulation overlay then activated the Westland's retraction catch. There was a wet slithering sound as the wing folded. The steering bar hinged up and back. He grappled with the frame, slapping the harness release. The ghost wing finished up as a fat damp cylinder three metres long, which he could just hold under one arm.

He scrambled up to the apex, and walked down to the end. When he peered over he could just make out the base of the wall, lined with tufts of grass and sickly dandelions. There was a monotonous dripping from the broken guttering. The roof would give them ample clearance for a swoop launch after they had completed the mission, a genuine running jump. Of course, they had both been trained to launch from a much lower height, and a shallower slope. But those lessons had been an uncomfortably long time ago now.