Andrew banked fractionally to the right, to pass the knoll. Michael conformed, peering ahead over the edge of his cockpit. Would she be there? It was too early, the knoll was bare, He felt the slide of disappointment and dread. Then he saw her, she was galloping up the pathway towards the crest. The big white stallion lunging powerfully under her slim girlish body.

The girl on the white horse was their good-luck talisman. If she was there waiting on the knoll to wave them away, all would be well. Today, when they were going against the balloons, they needed her, how desperately they needed her benediction.

She reached the crest of the knoll and reined the stallion down. just a few seconds before they drew level she whipped the hat off her head and the thick dark bush of her hair burst from under it. She waved the hat, and Andrew waggled his wings as he roared past.

Michael edged in closer to the crest. The white stallion backed up and nodded nervously as the yellow machine came bellowing at him, but the girl sat him easily, waving gaily. Michael wanted to see her face. He was almost at the same height as the top of the hillock and very close to where she sat. For an instant he looked into her eyes.

They were huge and dark, and he felt his heart trip. He touched his helmet in salute, and he knew now, deep down, that it would go well this day, then he put the memory of those eyes from his mind and looked ahead.

Ten miles ahead, where the low chalk ridges ran across their front, he saw with relief that he had been right, the breeze had not yet dispersed the morning mist that hung in the valleys. The chalk ridges were horribly chewed by shellfire, no vegetation remained upon them, the stumps of the shattered oak trees were nowhere as tall as a man's shoulder, and the shell craters overlapped each other, brimming with stagnant water. The ridges had been fought over, month after month, but at the moment they were in Allied hands, taken at the beginning of the preceding winter at a cost in human lives that challenged belief.

The leprous and pockmarked earth seemed deserted, but it was peopled by the legions of the living and the dead rotting together in the waterlogged earth. The smell of death home on the breeze reached even to the men in the low flying machines, an obscenity that coated the back of their throats and made them gag.

Behind the ridges the Allied troops, South Africans and New Zealanders of the Third Army, were preparing reserve positions as a contingency measure, for should the Allied offensive which was being prepared upon the Somme river further to the west fail, then all the fury of the German counter-attack would be unleashed upon them The preparation of the new line of defences was being seriously hampered by the massed German artillery to the north of the ridges, which deluged the area with an almost continuous barrage of high explosive. As they roared towards the front, Michael could see the yellow haze from the bursting howitzer shells hanging in a poison bank below the ridges, and he could imagine the anguish of the men toiling in the mud, harassed by the unremitting fall of explosives.

As Michael raced towards the ridges, the sound of the barrage rose above even the thunder of the big rotary Le Rhone engine and the buffeting rush of the slipstream.

The barrage was like the sound of storm surf on a rocky shore, like the beat of a demented drummer, like the fevered pulse of this sick, mad world, and Michael's fierce resentment at the men who had ordered them to go against the balloons abated as the roar of the barrage mounted. It was work that must be done, he realized it when he saw this dreadful suffering.

Yet the balloons were the most feared and hated targets that any man could fly against, that was why Andrew Killigerran would send nobody else. Michael saw them now, like fat silver slugs hanging in the dawn sky high above the ridges. One was directly ahead, the other a few miles further east. At this range the cables that tethered them to earth were invisible, and the wicker basket from which the observers obtained a grandstand view over the Allied rear areas were merely dark specks suspended beneath the shining spheres of hydrogen-filled silk.

At that moment there was a shocking disruption of air that hit the Sopwiths and rocked their wings, and immediately ahead of them a fountain of smoke and flame shot into the sky, rolling upon itself, black and bright orange, rising anvil-headed, high above the low-flying Sopwiths, forcing them to bank away steeply to avoid its fiery pillar. A German shell directed from one of the balloons had hit a forward Allied ammunition dump, end Michael felt his fear and resentment shrivel, to be replaced by a burning hatred of the gunners and of the men hanging in the sky, with eyes like vultures, calling down death with cold dispassion.

Andrew turned back towards the ridges, leaving the tall column of smoke on their right wingtips, and he dropped lower and still lower until his undercarriage was skimming the tops of the sandbagged parapets and they could see the South African troops moving in file along the Communication trenches, dun-coloured beasts of burden, not really human, toiling under the weight of their packs and equipment. Very few of them bothered to look up as the gaily painted machines thundered overhead. Those that did had grey, mud-streaked faces, the expression dulled and the eyes blank.

Ahead of them opened the mouth of one of the low passes that bisected the chalk ridges. The pass was filled with the morning mist. With the thrust of the dawn breeze agitating it, the mist bank undulated softly as though the earth was making love beneath a silver eiderdown.

There was the rattle of a Vickers machine-gun close ahead. Andrew was testfiring his weapon. Michael turned slightly out of line to clear his front and fired a short burst. The phosphorus-tipped incendiary bullets spun pretty white trails in the clear air.

Michael turned back into line behind Andrew and they hurtled into the mist, entering a new dimension of light and muted sound. The diffused light spun rainbow-coloured haloes around both aircraft and the moisture condensed on Michael's goggles.

He lifted them on to his forehead and peered ahead.

The previous afternoon, Andrew and Michael had carefully reconnoitred this narrow pass between the ridges, reassuring themselves that there were no obstacles or obstructions, and memorizing the way it twisted and turned through the higher ground, and yet it was still a perilous passage, with visibility down to 600 feet or less and the chalky slopes rising steeply at each wingtip.

Michael closed up on the green tailplane and flew on that alone, trusting Andrew to take him through, while the icy cold of the mist ate corrosively through his clothing and numbed his fingertips through the leather gauntlets.

Ahead of him Andrew banked steeply, and as Michael followed him round, he caught a glimpse of the barbed wire, brown with rust and tangled like bracken beneath his wheels.

No man's land, he muttered, and then the German front lines flashed beneath them, a mere glimpse of parapets beneath which crouched men in field-grey uniforms and those ugly coal-scuttle helmets.

Seconds later they burst out of the mist bank into a world lit by the first low rays of the sun, into a sky that dazzled them with its brilliance, and Michael realized that they had achieved total surprise. The mist bank had hidden them from the observers in the balloon and it had deadened the beat of their engines.

Directly ahead, the first balloon hung suspended in the sky, 1500 feet above them. Its steel anchor-cable, fine as a spider's strand of gossamer, led down to the ugly black steam winch half-buried in its emplacement of sandbags.

It looked utterly vulnerable, until Michael's eye dropped to the peaceful-seeming fields beneath the balloon, and there were the guns.