The first mistake, and the one that led to all the others, he was still unaware of. That was the fact that for the greater part of the first day, misled by his inaccurate Northseeker, he had been travelling far to the east of his intended course. When the influence of the iron deposits in the Red Hills was finally behind him, and his Northseeker returned to a true heading, the damage was already done. With every kilometre, he had diverged farther from the course that he thought he was taking. Now he was travelling parallel to it, but kilometres from where he thought he was.
His second mistake was to convince himself that he had seen the landmarks he was seeking. Admittedly, he had seen no flat-topped hill. But he told himself that he must have passed it without recognising it, rationalising to himself the fact that its shape had undoubtedly changed over the years from the distinctive profile that Selethen's chart indicated.
The low bank that he had seen late the previous afternoon bore no real resemblance to a line of cliffs. But, needing to believe that he had seen the cliffs, he convinced himself that he really had. He had seen no caves, and the chart showed that the cliffs had been honeycombed with them. Instead, he reassured himself that the caves were invisible because they had been shrouded in late afternoon shadow.
Now, to settle the question once and for all, he should see a balancing rock formation some time in the next few hours – a formation where a large rock balanced precariously on top of a smaller. At least, he told himself with a growing sense of foreboding, a feature like that would be unmistakable.
Unless the big rock had fallen off the smaller one overnight, he added grimly.
He needed to see that formation because his water supply was becoming alarmingly depleted. The first water-skin was empty. The second was less than half full. He had tried to ration himself severely but the heat simply drained energy from him so that he had to drink or fall senseless to the ground.
He consoled himself with the thought that, once he saw the balancing rocks and fixed his position, the water problem would be solved. A few kilometres from those rocks, a soak was marked on the chart – a small depression in a dried-up river-bed where water seeped slowly to the surface. Once there, all he would have to do was dig down a metre or so and wait while water filled the hole. It might be muddy and unpleasant, he knew. But it would be drinkable. And with his waterskins refilled and his location established once and for all, he would be able to strike out for one of the wells.
Sometime in the next few hours, he simply had to see the balancing rock formation or he was lost – figuratively as well as literally. As a result, he had to trust his map and his Northseeker and continue to believe that sooner or later, he would see those rocks. He simply had no alternative course of action.
It was this growing fatalism that led to his final, and most serious, mistake. Obsessed with the need to find the balancing rocks, and validate his course of action so far, he continued to ride through the hottest hours of the day.
Experienced desert travellers like Selethen didn't do this, he knew. But again, he rationalised. Selethen could navigate by the stars and didn't need daylight to sight landmarks and reference points. That meant he could afford the time spent resting in the middle of the day. But Will had an urgent need to find that water soak and surely a few hours of heat wouldn't do too much harm.
So he rode on, the heat battering down on him like a physical force as the sun rose higher in the sky. The air itself was superheated so that it almost scorched his throat and lungs when he breathed it in. It seemed that the all-pervading heat had sucked the very oxygen out of the air so that he gasped and panted for breath.
As well as the heat, the glare was a constant torture, forcing him to look into the shimmering distance with his eyes screwed almost shut.
Beneath him, Arrow plodded on, head down, feet dragging. Will was alarmed by the horse's rapid deterioration, having no idea that his own condition was even worse.
'Time for some water, boy,' he said. His voice was little more than a croak, forcing itself out through his dry throat and mouth.
He swung down from the saddle, his body stiff and awkward. He staggered a few paces as he touched the ground, having to steady himself against the horse's flank. Arrow stood unmoving, head drooped almost to the ground. Then he shifted his weight to his left side, seeming to favour his right front hoof. Already, after only a few seconds standing, Will could feel the blazing heat of the ground burning up through the soles of his boots. For Arrow's unprotected hooves, it must be torture, he thought.
'I'll take care of that in a minute,' he told the horse. 'First we'll drink.'
He fumbled with the ties attaching the folding leather bucket behind the saddle and dropped the bucket onto the ground. He laughed briefly.
'Just as well it wasn't full,' he told Arrow. The horse didn't respond. Setting the bucket down carefully, making sure he had placed it on a flat surface, Will took the remaining waterskin and unstoppered it carefully. He was painfully aware of how light it was now. As he poured carefully, Arrow's head turned towards the sound. The horse made a low grumbling noise in his throat.
'Hold your horses,' he said. Then he laughed again at the idea of telling his horse to hold his horses.
'Not that you're my horse, really,' he continued. 'But you're a good horse for all that.'
A part of his mind was a little concerned by the fact that he was laughing and joking with his horse. He had the strange sensation that he was standing to one side, watching himself and Arrow, and he frowned at this irrational behaviour. He shook the ridiculous notion away and held the bucket for Arrow to drink.
As ever, he felt his own mouth and throat working as he watched the horse drink. But, whereas the previous day his mouth had been thick and gummy feeling, today it was dry and swollen, all excess moisture gone from it.
Arrow finished, his big tongue futilely searching the seams of the bucket where a few last drops might be hidden. Will had become accustomed to the horse's almost philosophical acceptance of the amount of water he was given. This time, however, Arrow raised his head and nosed insistently around the waterskin slung over Will's shoulders. It was another indication of how their condition was worsening. The horse's training was overcome by its need for water.
Will pushed the questing muzzle away. 'Sorry, boy,' he said, almost incoherently. 'Later.'
He took two small sips himself, holding each one in his mouth, making it last, before letting it trickle slowly down his throat. Then, reluctantly, he re-stoppered the water skin and laid it in the scant shade of a thornbush.
He raised Arrow's left front hoof to examine it. The horse grumbled and shifted awkwardly. There was no visible injury but when he laid his palm on the soft centre of the hoof, he could feel the heat there. The desert ground was burning Arrow's unprotected feet. Will appreciated it even more now that he was standing. The heat was all around them. It beat down from the sun, hit the desert floor and struck upwards again. At least when he was riding Arrow he had a little relief from it.
He untied his blanket from behind the saddle and cut it into squares and strips. Then he wrapped the little horse's hoofs with pieces of the blanket, padding the underside with several folded layers, and tying the whole thing in place with thin strips. He'd be cold when night fell, he knew. But he'd be in a worse spot if his horse became lame.
Arrow seemed to be standing more comfortably, no longer leaning to his right side. Will took his bridle and led him a few paces, walking backwards to watch his gait. The horse didn't seem to be favouring either side now, he saw with some relief.