He picked up the knife again. As well as the clear and obvious feeling he got when he touched a point that would open to his own world, there had been another kind of sensation he'd touched more than once: a quality of resonance, like the feeling of striking a heavy wooden drum, except of course that it came, like every other one, in the tiniest movement through the empty air.

There it was. He moved away and felt somewhere else: there it was again.

He cut through and found that his guess was right. The resonance meant that the ground in the world he'd opened was in the same place as this one. He found himself looking at a grassy upland meadow under an overcast sky, in which a herd of placid beasts was grazing-animals such as he'd never seen before-creatures the size of bison, with wide horns and shaggy blue fur and a crest of stiff hair along their backs.

He stepped through. The nearest animal looked up incuriously and then turned back to the grass. Leaving the window open, Will, in the other-world meadow, felt with the knifepoint for the familiar snags and tried them.

Yes, he could open his own world from this one, and he was still high above the farms and hedges; and yes, he could easily find the solid resonance that meant the Cittagazze-world he'd just left.

With a deep sense of relief, Will went back to the camp by the lake, closing everything behind him. Now he could find his way home; now he would not get lost; now he could hide when he needed to, and move about safely.

With every increase in his knowledge came a gain in strength. He sheathed the knife at his waist and swung the rucksack over his shoulder.

"Well, are you ready now?" said that sarcastic voice.

"Yes. I'll explain if you like, but you don't seem very interested."

"Oh, I find whatever you do a source of perpetual fascination. But never mind me. What are you going to say to these people who are coming?"

Will looked around, startled. Farther down the trail-a long way down-there was a line of travelers with packhorses, making their way steadily up toward the lake. They hadn't seen him yet, but if he stayed where he was, they would soon.

Will gathered up his father's cloak, which he'd laid over a rock in the sun. It weighed much less now that it was dry. He looked around: there was nothing else he could carry.

"Let's go farther on," he said.

He would have liked to retie the bandage, but it could wait. He set off along the edge of the lake, away from the travelers, and the angel followed him, invisible in the bright air.

Much later that day they came down from the bare mountains onto a spur covered in grass and dwarf rhododendrons. Will was aching for rest, and soon, he decided, he'd stop.

He'd heard little from the angel. From time to time Balthamos had said, "Not that way," or "There is an easier path to the left," and he'd accepted the advice; but really he was moving for the sake of moving, and to keep away from those travelers, because until the other angel came back with more news, he might as well have stayed where they were.

Now the sun was setting, he thought he could see his strange companion. The outline of a man seemed to quiver in the light, and the air was thicker inside it.

"Balthamos?" he said. "I want to find a stream. Is there one nearby?"

"There is a spring halfway down the slope," said the angel, "just above those trees."

"Thank you," said Will.

He found the spring and drank deeply, filling his canteen. But before he could go on down to the little wood, there came an exclamation from Balthamos, and Will turned to see his outline dart across the slope toward-what? The angel was visible only as a flicker of movement, and Will could see him better when he didn't look at him directly; but he seemed to pause, and listen, and then launch himself into the air to skim back swiftly to Will.

"Here!" he said, and his voice was free of disapproval and sarcasm for once. "Baruch came this way! And there is one of those windows, almost invisible. Come-come. Come now."

Will followed eagerly, his weariness forgotten. The window, he saw when he reached it, opened onto a dim, tundra-like landscape that was flatter than the mountains in the Cittagazze world, and colder, with an overcast sky. He went through, and Balthamos followed him at once.

"Which world is this?" Will said.

"The girl's own world. This is where they came through. Baruch has gone ahead to follow them."

"How do you know? Do you read his mind?"

"Of course I read his mind. Wherever he goes, my heart goes with him; we feel as one, though we are two."

Will looked around. There was no sign of human life, and the chill in the air was increasing by the minute as the light failed.

"I don't want to sleep here," he said. "We'll stay in the Ci'gazze world for the night and come through in the morning. At least there's wood back there, and I can make a fire. And now I know what her world feels like, I can find it with the knife... Oh, Balthamos? Can you take any other shape?"

"Why would I wish to do that?"

"In this world human beings have daemons, and if I go about without one, they'll be suspicious. Lyra was frightened of me at first because of that. So if we're going to travel in her world, you'll have to pretend to be my daemon, and take the shape of some animal. A bird, maybe. Then you could fly, at least."

"Oh, how tedious."

"Can you, though?"

"I could could..."

"Do it now, then. Let me see."

The form of the angel seemed to condense and swirl into a little vortex in midair, and then a blackbird swooped down onto the grass at Will's feet.

"Fly to my shoulder," said Will.

The bird did so, and then spoke in the angel's familiar acid tone: "I shall only do this when it's absolutely necessary. It's unspeakably humiliating."

"Too bad," said Will. "Whenever we see people in this world, you become a bird. There's no point in fussing or arguing. Just do it."

The blackbird flew off his shoulder and vanished in midair, and there was the angel again, sulking in the half-light. Before they went back through, Will looked all around, sniffing the air, taking the measure of the world where Lyra was captive.

"Where is your companion now?" he said.

"Following the woman south."

"Then we shall go that way, too, in the morning."

Next day Will walked for hours and saw no one. The country consisted for the most part of low hills covered in short dry grass, and whenever he found himself on any sort of high point, he looked all around for signs of human habitation, but found none. The only variation in the dusty brown-green emptiness was a distant smudge of darker green, which he made for because Balthamos said it was a forest and there was a river there, which led south. When the sun was at its height, he tried and failed to sleep among some low bushes; and as the evening approached, he was footsore and weary.

"Slow progress," said Balthamos sourly.

"I can't help that," said Will. "If you can't say anything useful, don't speak at all."

By the time he reached the edge of the forest, the sun was low and the air heavy with pollen, so much so that he sneezed several times, startling a bird that flew up shrieking from somewhere nearby.

"That was the first living thing I've seen today," Will said.

"Where are you going to camp?" said Balthamos.

The angel was occasionally visible now in the long shadows of the trees. What Will could see of his expression was petulant.

Will said, "I'll have to stop here somewhere. You could help look for a good spot. I can hear a stream-see if you can find it."

The angel disappeared. Will trudged on, through the low clumps of heather and bog myrtle, wishing there was such a thing as a path for his feet to follow, and eyeing the light with apprehension: he must choose where to stop soon, or the dark would force him to stop without a choice.

"Left," said Balthamos, an arm's length away. "A stream and a dead tree for firewood. This way..."

Will followed the angel's voice and soon found the spot he described. A stream splashed swiftly between mossy rocks, and disappeared over a lip into a narrow little chasm dark under the overarching trees. Beside the stream, a grassy bank extended a little way back to bushes and undergrowth.

Before he let himself rest, he set about collecting wood, and soon came across a circle of charred stones in the grass, where someone else had made a fire long before. He gathered a pile of twigs and heavier branches and with the knife cut them to a useful length before trying to get them lit. He didn't know the best way to go about it, and wasted several matches before he managed to coax the flames into life.

The angel watched with a kind of weary patience.

Once the fire was going, Will ate two oatmeal biscuits, some dried meat, and some Kendal Mint Cake, washing it down with gulps of cold water. Balthamos sat nearby, silent, and finally Will said: "Are you going to watch me all the time? I'm not going anywhere."

"I'm waiting for Baruch. He will come back soon, and then I shall ignore you, if you like."

"Would you like some food?"

Balthamos moved slightly: he was tempted.

"I mean, I don't know if you eat at all," Will said, "but if you'd like something, you're welcome."

"What is that..." said the angel fastidiously, indicating the Kendal Mint Cake.

"Mostly sugar, I think, and peppermint. Here."

Will broke off a square and held it out. Balthamos inclined his head and sniffed. Then he picked it up, his fingers light and cool against Will's palm.

"I think this will nourish me," he said. "One piece is quite enough, thank you."

He sat and nibbled quietly. Will found that if he looked at the fire, with the angel just at the edge of his vision, he had a much stronger impression of him.

"Where is Baruch?" he said. "Can he communicate with you?"

"I feel that he is close. He'll be here very soon. When he returns, we shall talk. Talking is best."

And barely ten minutes later the soft sound of wingbeats came to their ears, and Balthamos stood up eagerly. The next moment, the two angels were embracing, and Will, gazing into the flames, saw their mutual affection. More than affection: they loved each other with a passion.

Baruch sat down beside his companion, and Will stirred the fire, so that a cloud of smoke drifted past the two of them. It had the effect of outlining their bodies so that he could see them both clearly for the first time. Balthamos was slender; his narrow wings were folded elegantly behind his shoulders, and his face bore an expression that mingled haughty disdain with a tender, ardent sympathy, as if he would love all things if only his nature could let him forget their defects. But he saw no defects in Baruch, that was clear. Baruch seemed younger, as Balthamos had said he was, and was more powerfully built, his wings snow-white and massive. He had a simpler nature; he looked up to Balthamos as to the fount of all knowledge and joy. Will found himself intrigued and moved by their love for each other.

"Did you find out where Lyra is?" he said, impatient for news.

"Yes," said Baruch. "There is a Himalayan valley, very high up, near a glacier where the light is turned into rainbows by the ice. I shall draw you a map in the soil so you don't mistake it. The girl is captive in a cave among the trees, kept asleep by the woman."

"Asleep? And the woman's alone? No soldiers with her?"

"Alone, yes. In hiding."

"And Lyra's not harmed?"

"No. Just asleep, and dreaming. Let me show you where they are."

With his pale finger, Baruch traced a map in the bare soil beside the fire. Will took his notebook and copied it exactly. It showed a glacier with a curious serpentine shape, flowing down between three almost identical mountain peaks.

"Now," said the angel, "we go closer. The valley with the cave runs down from the left side of the glacier, and a river of meltwater runs through it. The head of the valley is here..."

He drew another map, and Will copied that; and then a third, getting closer in each time, so that Will felt he could find his way there without difficulty-provided that he'd crossed the four or five thousand miles between the tundra and the mountains. The knife was good for cutting between worlds, but it couldn't abolish distance within them.

"There is a shrine near the glacier," Baruch ended by saying, "with red silk banners half-torn by the winds. And a young girl brings food to the cave. They think the woman is a saint who will bless them if they look after her needs."

"Do they," said Will. "And she's hiding hiding... That's what I don't understand. Hiding from the Church?"

"It seems so."

Will folded the maps carefully away. He had set the tin cup on the stones at the edge of the fire to heat some water, and now he trickled some powdered coffee into it, stirring it with a stick, and wrapped his hand in a handkerchief before picking it up to drink.

A burning stick settled in the fire; a night bird called.

Suddenly, for no reason Will could see, both angels looked up and in the same direction. He followed their gaze, but saw nothing. He had seen his cat do this once: look up alert from her half-sleep and watch something or someone invisible come into the room and walk across. That had made his hair stand up, and so did this.

"Put out the fire," Balthamos whispered.

Will scooped up some earth with his good hand and doused the flames. At once the cold struck into his bones, and he began to shiver. He pulled the cloak around himself and looked up again.

And now there was something to see: above the clouds a shape was glowing, and it was not the moon.

He heard Baruch murmur, "The Chariot? Could it be?"

"What is it?" Will whispered.

Baruch leaned close and whispered back, "They know we're here. They've found us. Will, take your knife and-"

Before he could finish, something hurtled out of the sky and crashed into Balthamos. In a fraction of a second Baruch had leapt on it, and Balthamos was twisting to free his wings. The three beings fought this way and that in the dimness, like great wasps caught in a mighty spider's web, making no sound: all Will could hear was the breaking twigs and the brushing leaves as they struggled together.

He couldn't use the knife: they were all moving too quickly. Instead, he took the electric torch from the rucksack and switched it on.

None of them expected that. The attacker threw up his wings, Balthamos flung his arm across his eyes, and only Baruch had the presence of mind to hold on. But Will could see what it was, this enemy: another angel, much bigger and stronger than they were, and Baruch's hand was clamped over his mouth.

"Will!" cried Balthamos. "The knife-cut a way out-"

And at the same moment the attacker tore himself free of Baruch's hands, and cried: "Lord Regent! I have them! Lord Regent!"

His voice made Will's head ring; he had never heard such a cry. And a moment later the angel would have sprung into the air, but Will dropped his torch and leapt forward. He had killed a cliff-ghast, but using the knife on a being shaped like himself was much harder. Nevertheless, he gathered the great beating wings into his arms and slashed again and again at the feathers until the air was filled with whirling flakes of white, remembering even in the sweep of violent sensations the words of Balthamos: You have true flesh, we have not You have true flesh, we have not. Human beings were stronger than angels, stronger even than great powers like this one, and it was true: he was bearing the angel down to the ground.

The attacker was still shouting in that ear-splitting voice: "Lord Regent! To me, to me!" "Lord Regent! To me, to me!"

Will managed to glance upward and saw the clouds stirring and swirling, and that gleam-something immense-growing more powerful, as if the clouds themselves were becoming luminous with energy, like plasma.

Balthamos cried, "Will-come away and cut through, before he comes-"