Will and Lyra slept through the night and woke up when the sun struck their eyelids. They actually awoke within seconds of each other, with the same thought; but when they looked around, the Chevalier Tialys was calmly on guard close by.

"The force of the Consistorial Court has retreated," he told them. "Mrs. Coulter is in the hands of King Ogunwe, and on her way to Lord Asriel."

"How do you know?" said Will, sitting up stiffly. "Have you been back through the window?"

"No. We talk through the lodestone resonator. I reported our conversation," Tialys said to Lyra, "to my commander, Lord Roke, and he has agreed that we should go with you to the bear, and that once you have seen him, you will come with us. So we are allies, and we shall help you as much as we can."

"Good," said Will. "Then let's eat together. Do you eat our food?"

"Thank you, yes," said the Lady.

Will took out his last few dried peaches and the stale flat loaf of rye bread, which was all he had left, and shared it among them, though of course the spies did not take much.

"As for water, there doesn't seem to be any around here on this world," Will said. "We'll have to wait till we go back through before we can have a drink."

"Then we better do that soon," said Lyra.

First, though, she took out the alethiometer and asked if there was still any danger in the valley. No, came the answer, all the soldiers have gone, and the villagers are in their homes; so they prepared to leave.

The window looked strange in the dazzling air of the desert, giving onto the deep-shaded bush, a square of thick green vegetation hanging in the air like a painting. The Gallivespians wanted to look at it, and were astounded to see how it was just not there from the back, and how it only sprang into being when you came round from the side.

"I'll have to close it once we're through," Will said.

Lyra tried to pinch the edges together after they went through, but her fingers couldn't find it at all; nor could the spies, despite the fineness of their hands. Only Will could feel exactly where the edges were, and he did it cleanly and quickly.

"How many worlds can you enter with the knife?" said Tialys.

"As many as there are," said Will. "No one would ever have time to find out."

He swung his rucksack up and led the way along the forest path. The dragonflies relished the fresh, moist air and darted like needles through the shafts of sunlight. The movement of the trees above was less violent, and the air was cool and tranquil; so it was all the more shocking to see the twisted wreckage of a gyropter suspended among the branches, with the body of its African pilot, tangled in his seat belt, half out of the door, and to find the charred remains of the zeppelin a little farther up - soot-black strips of cloth, blackened struts and pipe work, broken glass, and then the bodies: three men burned to cinders, their limbs contorted and drawn up as if they were still threatening to fight.

And they were only the ones who had fallen near the path. There were other bodies and more wreckage on the cliff above and among the trees farther down. Shocked and silenced, the two children moved through the carnage, while the spies on their dragonflies looked around more coolly, accustomed to battle, noting how it had gone and who had lost most.

When they reached the top of the valley, where the trees thinned out and the rainbow-waterfalls began, they stopped to drink deeply of the ice-cold water.

"I hope that little girl's all right," said Will. "We'd never have got you away if she hadn't woken you up. She went to a holy man to get that powder specially."

"She is all right," said Lyra, " 'cause I asked the alethiometer, last night. She thinks we're devils, though. She's afraid of us. She probably wishes she'd never got mixed up in it, but she's safe all right."

They climbed up beside the waterfalls and refilled Will's canteen before striking off across the plateau toward the ridge where the alethiometer told Lyra that Iorek had gone.

And then there came a day of long, hard walking: no trouble for Will, but a torment to Lyra, whose limbs were weakened and softened after her long sleep. But she would sooner have her tongue torn out than confess how bad she felt; limping, tight-lipped, trembling, she kept pace with Will and said nothing. Only when they sat down at noon did she allow herself so much as a whimper, and then only when Will had gone apart to relieve himself.

The Lady Salmakia said, "Rest. There is no disgrace in being weary."

"But I don't want to let Will down! I don't want him to think I'm weak and holding him back."

"That's the last thing he thinks."

"You don't know," said Lyra rudely. "You don't know him any more than you know me."

"I know impertinence when I hear it," said the Lady calmly. "Do as I tell you now and rest. Save your energy for the walking."

Lyra felt mutinous, but the Lady's glittering spurs were very clear in the sunlight, so she said nothing.

The Lady's companion, the Chevalier, was opening the case of the lodestone resonator, and, curiosity overcoming resentment, Lyra watched to see what he did. The instrument looked like a short length of pencil made of dull gray-black stone, resting on a stand of wood, and the Chevalier swept a tiny bow like a violinist's across the end while he pressed his fingers at various points along the surface. The places weren't marked, so he seemed to be touching it at random, but from the intensity of his expression and the certain fluency of his movements, Lyra knew it was as skillful and demanding a process as her own reading of the alethiometer.

After several minutes the spy put the bow away and took up a pair of headphones, the earpieces no larger than Lyra's little fingernail, and wrapped one end of the wire tightly around a peg in the end of the stone, leading the rest along to another peg at the other end and wrapping it around that. By manipulating the two pegs and the tension on the wire between them, he could obviously hear a response to his own message.

"How does that work?" she said when he'd finished.

Tialys looked at her as if to judge whether she was genuinely interested, and then said, "Your scientists, what do you call them, experimental theologians, would know of something called quantum entanglement. It means that two particles can exist that only have properties in common, so that whatever happens to one happens to the other at the same moment, no matter how far apart they are. Well, in our world there is a way of taking a common lodestone and entangling all its particles, and then splitting it in two so that both parts resonate together. The counterpart to this is with Lord Roke, our commander. When I play on this one with my bow, the other one reproduces the sounds exactly, and so we communicate."

He put everything away and said something to the Lady. She joined him and they went a little apart, talking too quietly for Lyra to hear, though Pantalaimon became an owl and turned his great ears in their direction.

Presently Will came back and then they moved on, more slowly as the day went by and the track got steeper and the snow line nearer. They rested once more at the head of a rocky valley, because even Will could tell that Lyra was nearly finished: she was limping badly and her face was gray.

"Let me see your feet," he said to her, "because if they're blistered, I'll put some ointment on."

They were, badly, and she let him rub in the bloodmoss salve, closing her eyes and gritting her teeth.

Meanwhile, the Chevalier was busy, and after a few minutes he put his lodestone away and said, "I have told Lord Roke of our position, and they are sending a gyropter to bring us away as soon as you have spoken to your friend."

Will nodded. Lyra took no notice. Presently she sat up wearily and pulled on her socks and shoes, and they set off once more.

Another hour, and most of the valley was in shadow, and Will was wondering whether they would find any shelter before night fell; but then Lyra gave a cry of relief and joy.

"Iorek! Iorek!"

She had seen him before Will had. The bear-king was some way off still, his white coat indistinct against a patch of snow, but when Lyra's voice echoed out he turned his head, raised it to sniff, and bounded down the mountainside toward them.

Ignoring Will, he let Lyra clasp his neck and bury her face in his fur, growling so deep that Will felt it through his feet; but Lyra felt it as pleasure and forgot her blisters and her weariness in a moment.

"Oh, Iorek, my dear, I'm so glad to see you! I never thought I'd ever see you again - after that time on Svalbard - and all the things that've happened, is Mr. Scoresby safe? How's your kingdom? Are you all alone here?"

The little spies had vanished; at all events, there seemed to be only the three of them now on the darkening mountainside, the boy and the girl and the great white bear. As if she had never wanted to be anywhere else, Lyra climbed up as Iorek offered his back and rode proud and happy as her dear friend carried her up the last stretch of the way to his cave.

Will, preoccupied, didn't listen as Lyra talked to Iorek, though he did hear a cry of dismay at one point, and heard her say:

"Mr. Scoresby - oh no! Oh, it's too cruel! Really dead? You're sure, Iorek?"

"The witch told me he set out to find the man called Grumman," said the bear.

Will listened more closely now, for Baruch and Balthamos had told him some of this.

"What happened? Who killed him?" said Lyra, her voice shaky.

"He died fighting. He kept a whole company of Muscovites at bay while the man escaped. I found his body. He died bravely. I shall avenge him."

Lyra was weeping freely, and Will didn't know what to say, for it was his father whom this unknown man had died to save; and Lyra and the bear had both known and loved Lee Scoresby, and he had not.

Soon Iorek turned aside and made for the entrance to a cave, very dark against the snow. Will didn't know where the spies were, but he was perfectly sure they were nearby. He wanted to speak quietly to Lyra, but not till he could see the Gallivespians and know he wasn't being overheard.

He laid his rucksack in the cave mouth and sat down wearily. Behind him the bear was kindling a fire, and Lyra watched, curious despite her sorrow. Iorek held a small rock of some sort of ironstone in his left forepaw and struck it no more than three or four times on a similar one on the floor. Each time a scatter of sparks burst out and went exactly where Iorek directed them: into a heap of shredded twigs and dried grass. Very soon that was ablaze, and Iorek calmly placed one log and then another and another until the fire was burning strongly.

The children welcomed it, because the air was very cold now, and then came something even better: a haunch of something that might have been goat. Iorek ate his meat raw, of course, but he spitted its joint on a sharp stick and laid it to roast across the fire for the two of them.

"Is it easy, hunting up in these mountains, Iorek?" she said.

"No. My people can't live here. I was wrong, but luckily so, since I found you. What are your plans now?"

Will looked around the cave. They were sitting close to the fire, and the firelight threw warm yellows and oranges on the bear-king's fur. Will could see no sign of the spies, but there was nothing for it: he had to ask.

"King Iorek," he began, "my knife is broken - " Then he looked past the bear and said, "No, wait." He was pointing at the wall. "If you're listening," he went on more loudly, "come out and do it honestly. Don't spy on us."

Lyra and Iorek Byrnison turned to see who he was talking to. The little man came out of the shadow and stood calmly in the light, on a ledge higher than the children's heads, Iorek growled.

"You haven't asked Iorek Byrnison for permission to enter his cave," Will said. "And he is a king, and you're just a spy. You should show more respect."

Lyra loved hearing that. She looked at Will with pleasure, and saw him fierce and contemptuous.

But the Chevalier's expression, as he looked at Will, was displeased.

"We have been truthful with you," he said. "It was dishonorable to deceive us."

Will stood up. His daemon, Lyra thought, would have the form of a tigress, and she shrank back from the anger she imagined the great animal to show.

"If we deceived you, it was necessary," he said. "Would you have agreed to come here if you knew the knife was broken? Of course you wouldn't. You'd have used your venom to make us unconscious, and then you'd have called for help and had us kidnapped and taken to Lord Asriel. So we had to trick you, Tialys, and you'll just have to put up with it."

Iorek Byrnison said, "Who is this?"

"Spies," said Will. "Sent by Lord Asriel. They helped us escape yesterday, but if they're on our side, they shouldn't hide and eavesdrop on us. And if they do, they're the last people who should talk about dishonor."

The spy's glare was so ferocious that he looked ready to take on Iorek himself, never mind the unarmed Will; but Tialys was in the wrong, and he knew it. All he could do was bow and apologize.

"Your Majesty," he said to Iorek, who growled at once.

The Chevalier's eyes flashed hatred at Will, and defiance and warning at Lyra, and a cold and wary respect at Iorek. The clarity of his features made all these expressions vivid and bright, as if a light shone on him. Beside him the Lady Salmakia was emerging from the shadow, and, ignoring the children completely, she made a curtsy to the bear.

"Forgive us," she said to Iorek. "The habit of concealment is hard to break, and my companion, the Chevalier Tialys, And I, the Lady Salmakia, have been among our enemies for so long that out of pure habit we neglected to pay you the proper courtesy. We're accompanying this boy and girl to make sure they arrive safely in the care of Lord Asriel. We have no other aim, and certainly no harmful intention toward you, King Iorek Byrnison."

If Iorek wondered how any such tiny beings could cause him harm, he didn't show it; not only was his expression naturally hard to read, but he had his courtesy, too, and the Lady had spoken graciously enough.

"Come down by the fire," he said. "There is food enough and plenty if you are hungry. Will, you began to speak about the knife."

"Yes," said Will, "and I thought it could never happen, but it's broken. And the alethiometer told Lyra that you'd be able to mend it. I was going to ask more politely, but there it is: can you mend it, Iorek?"

"Show me."

Will shook all the pieces out of the sheath and laid them on the rocky floor, pushing them about carefully until they were in their right places and he could see that they were all there. Lyra held a burning branch up, and in its light Iorek bent low to look closely at each piece, touching it delicately with his massive claws and lifting it up to turn it this way and that and examine the break. Will marveled at the deftness in those huge black hooks.

Then Iorek sat up again, his head rearing high into the shadow.

"Yes," he said, answering exactly the question and no more.

Lyra said, knowing what he meant, "Ah, but will you, Iorek? You couldn't believe how important this is - if we can't get it mended then we're in desperate trouble, and not only us - "

"I don't like that knife," Iorek said. "I fear what it can do. I have never known anything so dangerous. The most deadly fighting machines are little toys compared to that knife; the harm it can do is unlimited. It would have been infinitely better if it had never been made."

"But with it - " began Will.

Iorek didn't let him finish, but went on, "With it you can do strange things. What you don't know is what the knife does on its own. Your intentions may be good. The knife has intentions, too."

"How can that be?" said Will.

"The intentions of a tool are what it does. A hammer intends to strike, a vise intends to hold fast, a lever intends to lift. They are what it is made for. But sometimes a tool may have other uses that you don't know. Sometimes in doing what you intend, you also do what the knife intends, without knowing. Can you see the sharpest edge of that knife?"

"No," said Will, for it was true: the edge diminished to a thinness so fine that the eye could not reach it.

"Then how can you know everything it does?"

"I can't. But I must still use it, and do what I can to help good things come about. If I did nothing, I'd be worse than useless. I'd be guilty."

Lyra was following this closely, and seeing Iorek still unwilling, she said:

"Iorek, you know how wicked those Bolvangar people were. If we can't win, then they're going to be able to carry on doing those kind of things forever. And besides, if we don't have the knife, then they might get hold of it themselves. We never knew about it when I first met you, Iorek, and nor did anyone, but now that we do, we got to use it ourselves, we can't just not. That'd be feeble, and it'd be wrong, too, it'd be just like handing it over to 'em and saying, 'Go on, use it, we won't stop you.' All right, we don't know what it does, but I can ask the alethiometer, can't I? Then we'd know. And we could think about it properly, instead of just guessing and being afraid."

Will didn't want to mention his own most pressing reason: if the knife was not repaired, he might never get home, never see his mother again; she would never know what had happened; she'd think he'd abandoned her as his father had done. The knife would have been directly responsible for both their desertions. He must use it to return to her, or never forgive himself.

Iorek Byrnison said nothing for a long time, but turned his head to look out at the darkness. Then he slowly got to his feet and stalked to the cave mouth, and looked up at the stars: some the same as those he knew, from the north, and some that were strange to him.

Behind him, Lyra turned the meat over on the fire, and Will looked at his wounds, to see how they were healing. Tialys and Salmakia sat silent on their ledge.

Then Iorek turned around.

"Very well, I shall do it on one condition," he said. "Though I feel it is a mistake. My people have no gods, no ghosts or daemons. We live and die and that is that. Human affairs bring us nothing but sorrow and trouble, but we have language and we make war and we use tools; maybe we should take sides. But full knowledge is better than half-knowledge. Lyra, read your instrument. Know what it is that you're asking. If you still want it then, I shall mend the knife."

At once Lyra took out the alethiometer and edged nearer to the fire so that she could see the face. The reading took her longer than usual, and when she blinked and sighed and came out of the trance, her face was troubled.

"I never known it so confused," she said. "There was lots of things it said. I think I got it clear. I think so. It said about balance first. It said the knife could be harmful or it could do good, but it was so slight, such a delicate kind of a balance, that the faintest thought or wish could tip it one way or the other... And it meant you, Will, it meant what you wished or thought, only it didn't say what would be a good thought or a bad one.

"Then... it said yes," she said, her eyes flashing at the spies. "It said yes, do it, repair the knife."

Iorek looked at her steadily and then nodded once.

Tialys and Salmakia climbed down to watch more closely, and Lyra said, "D'you need more fuel, Iorek? Me and Will could go and fetch some, I'm sure."

Will understood what she meant: away from the spies they could talk.

Iorek said, "Below the first spur on the track, there is a bush with resinous wood. Bring as much of that as you can."

She jumped up at once, and Will went with her.

The moon was brilliant, the path a track of scumbled footprints in the snow, the air cutting and cold. Both of them felt brisk and hopeful and alive. They didn't talk till they were well away from the cave.

"What else did it say?" Will said.

"It said some things I didn't understand then and I still don't understand now. It said the knife would be the death of Dust, but then it said it was the only way to keep Dust alive. I didn't understand it, Will. But it said again it was dangerous, it kept saying that. It said if we - you know - what I thought - "

"If we go to the world of the dead - "

"Yeah - if we do that - it said that we might never come back, Will. We might not survive."

He said nothing, and they walked along more soberly now, watching out for the bush that Iorek had mentioned, and silenced by the thought of what they might be taking on.

"We've got to, though," he said, "haven't we?"

"I don't know."

"Now we know, I mean. You have to speak to Roger, and I want to speak to my father. We have to, now."

"I'm frightened," she said.

And he knew she'd never admit that to anyone else.

"Did it say what would happen if we didn't?" he asked.

"Just emptiness, just blankness. I really didn't understand it, Will. But I think it meant that even if it is that dangerous, we should still try and rescue Roger. But it won't be like when I rescued him from Bolvangar; I didn't know what I was doing then, really, I just set off, and I was lucky. I mean there was all kinds of other people to help, like the gyptians and the witches. There won't be any help where we'd have to go. And I can see... In my dream I saw... The place was... It was worse than Bolvangar. That's why I'm afraid."

"What I'm afraid of," said Will after a minute, not looking at her at all, "is getting stuck somewhere and never seeing my mother again."

From nowhere a memory came to him: he was very young, and it was before her troubles began, and he was ill. All night long, it seemed, his mother had sat on his bed in the dark, singing nursery rhymes, telling him stories, and as long as her dear voice was there, he knew he was safe. He couldn't abandon her now. He couldn't! He'd look after her all his life long if she needed it.

And as if Lyra had known what he was thinking, she said warmly:

"Yeah, that's true, that would be awful... You know, with my mother, I never realized... I just grew up on my own, really; I don't remember anyone ever holding me or cuddling me, it was just me and Pan as far back as I can go... I can't remember Mrs. Lonsdale being like that to me; she was the housekeeper at Jordan College, all she did was make sure I was clean, that's all she thought about... oh, and manners... But in the cave, Will, I really felt - oh, it's strange, I know she's done terrible things, but I really felt she was loving me and looking after me... She must have thought I was going to die, being asleep all that time - I suppose I must've caught some disease - but she never stopped looking after me. And I remember waking up once or twice and she was holding me in her arms... I do remember that, I'm sure...That's what I'd do in her place, if I had a child."

So she didn't know why she'd been asleep all that time. Should he tell her, and betray that memory, even if it was false? No, of course he shouldn't.

"Is that the bush?" Lyra said.

The moonlight was brilliant enough to show every leaf. Will snapped off a twig, and the piney resinous smell stayed strongly on his fingers.

"And we en't going to say anything to those little spies," she added.

They gathered armfuls of the bush and carried them back up toward the cave.