It was unbearably hot parked in the sunlight at the edge of the road. Making up his mind suddenly, Kuryakin swung over the VW's wheel and set off the way he had come, following the convoy back towards the dam.

Three or four miles after the junction with the road to San Felipe village, the valley narrowed and the sides became steep and rocky. Soon he was driving along a serpentine defile above whose thickly wooded lower slopes great cliffs reared skywards.

Abruptly the gorge divided: the river in its stony bed burrowed beneath the road and was seen to be emerging from the canyon on the right, while the tributary valley on the left was marked only by a dried-up watercourse showing not even a trickle of moisture. The road forked too, though in a contrary sense - for while the highway to the south twisted away towards the pass at the head of the minor valley, the road following the main gorge was blocked a hundred yards further on by wire mesh gate on steel frames. And the smooth blacktop which had distinguished the highway ever since Getuliana swerved aside from the main road and continued beyond the gates to where, a half mile away, the great bulk of the dam itself was visible around a bend in the valley. Beyond a cracked and peeling sign pointing to AGUACALINDA - SANTA MARIA DA CONCEICAO - GOIÁS the trunk road relapsed at once into an unsurfaced dirt-track alternating chassis-breaking potholes with extrusions of naked bed rock. Clearly the pavement had been laid only to assist the contractors in moving materials from landing strip to dam, and the hell with local communications.

Illya had no means of knowing how wide the reservoir might be in the drowned valley behind the barrage, but the actual dam was one of the highest he had ever seen. From the curved lip spanning the gorge high up against the blue wedge of sky, the great curtain of concrete plunged downwards in three stages like a frozen wave. At each level, multiple arches housing the sluices linked blockhouses from which the giant-bore pipes dropped to the hydroelectric generating station below. And around the power station an ancillary web of transformer housings, masts, insulators and pylons had been neatly spun. Towering between the age-old rock faces of that desolate valley, the dam was a testament to the ingenuity of man, a beautiful piece of engineering.

The agent drove slowly up to the wire gates blocking the road to the power station. On either side as far as he could see, ten-foot wire fencing behind a deep ditch guarded the boundaries of the property. A man came out of a small concrete building just inside the gates. He was dressed in the same khaki and black uniform worn by the guards Illya had seen in the convoy. And he was carrying a machine pistol.

"What do you want?" he called over the top of the gates. His voice was not friendly.

"This is the San Felipe dam, isn't it?" Illya called, putting his head out of the car window. "The Moraes-Wassermann project?"

The guard continued staring at him, saying nothing.

"I am a construction engineer… in Brazil on a short visit to survey progress in hydroelectric works, bridging, and so on. They tell me the barrage here, is particularly interesting and I wondered -"

"This is private property," the man said. "On your way.

"Most dams are on private property, but that does not mean that a courteously worded request -"

"I said beat it," the guard snapped, his sullen face scowling. "We don't like snoopers around here. Like I said, it's private, see. Now get out."

"But how can I get to see the artificial lake…"

"You can't. You can either go back to San Felipe or go on to Aguacalinda or Goiás - if you like driving over bare rock. And you won't see the lake from either road, because it's not overlooked by any goddamn road. It's too high up and the rocks are too steep around it… There's a third choice: you stay here one minute more, I'll call out the site police and have you towed off our property. And they're not gentle."

"Well, really… I'm not on your property anyway. I'm outside the gates."

"You're on private property the moment you leave that fork. Now are you getting the hell out of here, Or…"

Hoping that he had displayed the correct amount of outraged resentment to pass for a visitor consumed merely with idle curiosity, Illya turned the Volkswagen and drove on towards Aguacalinda. Although the surface was very bad, the road appeared - judging from the multiplicity of tire marks in the dust - to carry fairly heavy traffic.

Such few houses that he saw, however - mainly peasant huts or the dwellings of subsistence farmers who scratched a living from the stony soil - were strung out along the hillside far from the road without even a track wide enough for a vehicle leading to them. So the traffic must either be heading all the way south to Goiás and the next state (which seemed unlikely) or to some other place further up the valley. Yet the maps he had, admittedly imprecise, showed no sign of any large habitation before Aguacalinda... which was some distance on the other side of the pass and was in any case smaller than San Felipe itself.

If the maps were in any way correct, the valley which had been drowned by the reservoir curved around and ran almost parallel with the one he was in right up to the watershed. Between the trees to his right every now and then he could see the high wire fence enclosing the property - which seemed to confirm the geographers in their mapping.

When he was two or three miles from the gates and, the guard house, he stopped the car under a grove of trees and climbed the steep side of the valley on the opposite side of the road from the fence.

The trees were dense and for the first half hour it was tough going. Then he came out onto a stretch of rocky ground where it was easier to pick his way. And finally he stopped where the rough slope met the vertical cliffs lining the gorge.

But the guard had been right. Even from here he could see nothing of the artificial lake beyond the far side of the defile. Behind the opposite rock face the barren ground rose again and cut off his view before it dropped to the next valley. At his feet, the road and the dried up river bed snaked through the trees.

He scrambled back down the mountainside and crossed the road to examine the wire fence.

As he had expected, there were alarm wires threaded along its length - although these were surprisingly not electric, but the simple mechanical kind which actuated buzzers or bells. Every few yards there were notices saying: DANGER! THIS IS PRIVATE PROPERTY. KEEP OFF! WARNING IS GIVEN TO TRESPASSERS THAT THE GROUND BEYOND THIS FENCE IS PATROLLED BY ARMED GUARDS AND BY DOGS.

He returned to the car and drove on. After another mile and a half, the fence curved away up the steepening hillside to pass around a sizable property bordering the road. There was a long, low, two-storied house with wooden balconies, a group of outbuildings, and palm trees behind a high hedge of some shrub. An estancia, would it be? A hacienda?... No, that was Spanish, surely. But anyway it was a demesne very different in style from the poor cabins scattered along the other side of the valley.

It was when he had gone about ten minutes' drive past the place, and the road was beginning to zigzag up wards, obviously on its way to the saddle across the watershed, that he realized the evidence of heavy traffic was no longer visible. The dusty spaces between the pot holes were bare of tire marks.

He turned and drove back towards the property, pulling the VW off the road a quarter of a mile short of it and running the car behind a thicket to hide it from the road.

Once again he forced his way up the hillside to the rock face and scanned the valley below through field glasses.