Ysabell sat up in bed.

The knocking came again, soft and urgent. She pulled the covers up to her chin.

“Who is it?” she whispered.

“It’s me, Mort,” came the hiss under the door. “Let me in, please!”

“Wait!”

Ysabell scrambled frantically on the bedside table for the matches, knocking over a bottle of toilet water and dislodging a box of chocolates that was now mostly discarded wrappers. Once she’d got the candle alight she adjusted its position for maximum effect, tweaked the line of her nightdress into something more revealing, and said: “It’s not locked.”

Mort staggered into the room, smelling of horses and frost and scumble.

“I hope,” said Ysabell archly, “that you have not forced your way in here in order to take advantage of your position in this household.”

Mort looked around him. Ysabell was heavily into frills. Even the dressing table seemed to be wearing a petticoat. The whole room wasn’t so much furnished as lingeried.

“Look, I haven’t got time to mess around,” he said. “Bring that candle into the library. And for heaven’s sake put on something sensible, you’re overflowing.”

Ysabell looked down, and then her head snapped up.

“Well!”

Mort poked his head back round the door. “It’s a matter of life and death,” he added, and disappeared.

Ysabell watched the door creak shut after him, revealing the blue dressing gown with the tassels that Death had thought up for her as a present last Hogswatch and which she hadn’t the heart to throw away, despite the fact that it was a size too small and had a rabbit on the pocket.

Finally she swung her legs out of bed, slipped into the shameful dressing gown, and padded out into the corridor. Mort was waiting for her.

“Won’t father hear us?” she said.

“He’s not back. Come on.”

“How can you tell?”

“The place feels different when he’s here. It’s—it’s like the difference between a coat when it’s being worn and when it’s hanging on a hook. Haven’t you noticed?”

“What are we doing that’s so important?”

Mort pushed open the library door. A gust of warm, dry air drifted out, and the door hinges issued a protesting creak.

“We’re going to save someone’s life,” he said. “A princess, actually.”

Ysabell was instantly fascinated.

“A real princess? I mean can she feel a pea through a dozen mattresses?”

“Can she—?” Mort felt a minor worry disappear. “Oh. Yes. I thought Albert had got it wrong.”

“Are you in love with her?”

Mort came to a standstill between the shelves, aware of the busy little scritchings inside the book covers.

“It’s hard to be sure,” he said. “Do I look it?”

“You look a bit flustered. How does she feel about you?”

“Don’t know.”

“Ah,” said Ysabell knowingly, in the tones of an expert. “Unrequited love is the worst kind. It’s probably not a good idea to go taking poison or killing yourself, though,” she added thoughtfully. “What are we doing here? Do you want to find her book to see if she marries you?”

“I’ve read it, and she’s dead,” said Mort. “But only technically. I mean, not really dead.”

“Good, otherwise that would be necromancy. What are we looking for?”

“Albert’s biography.”

“What for? I don’t think he’s got one.”

“Everyone’s got one.”

“Well, he doesn’t like people asking personal questions. I looked for it once and I couldn’t find it. Albert by itself isn’t much to go on. Why is he so interesting?” Ysabell lit a couple of candles from the one in her hand and filled the library with dancing shadows.

“I need a powerful wizard and I think he’s one.”

“What, Albert?”

“Yes. Only we’re looking for Alberto Malich. He’s more than two thousand years old, I think.”

“What, Albert?”

“Yes. Albert.”

“He never wears a wizard’s hat,” said Ysabell doubtfully.

“He lost it. Anyway, the hat isn’t compulsory. Where do we start looking?”

“Well, if you’re sure…the Stack, I suppose. That’s where father puts all the biographies that are more than five hundred years old. It’s this way.”

She led the way past the whispering shelves to a door set in a cul-de-sac. It opened with some effort and the groan of the hinges reverberated around the library; Mort fancied for a moment that all the books paused momentarily in their work just to listen.

Steps led down into the velvet gloom. There were cobwebs and dust, and air that smelled as though it had been locked in a pyramid for a thousand years.

“People don’t come down here very often,” said Ysabell. “I’ll lead the way.”

Mort felt something was owed.

“I must say,” he said, “you’re a real brick.”

“You mean pink, square and dumpy? You really know how to talk to a girl, my boy.”

“Mort,” said Mort automatically.

The Stack was as dark and silent as a cave deep underground. The shelves were barely far enough apart for one person to walk between them, and towered up well beyond the dome of candlelight. They were particularly eerie because they were silent. There were no more lives to write; the books slept. But Mort felt that they slept like cats, with one eye open. They were aware.

“I came down here once,” said Ysabell, whispering. “If you go far enough along the shelves the books run out and there’s clay tablets and lumps of stone and animal skins and everyone’s called Ug and Zog.”

The silence was almost tangible. Mort could feel the books watching them as they tramped through the hot, silent passages. Everyone who had ever lived was here somewhere, right back to the first people that the gods had baked out of mud or whatever. They didn’t exactly resent him, they were just wondering about why he was here.

“Did you get past Ug and Zog?” he hissed. “There’s a lot of people would be very interested to know what’s there.”

“I got frightened. It’s a long way and I didn’t have enough candles.”

“Pity.”

Ysabell stopped so sharply that Mort cannoned into the back of her.

“This would be about the right area,” she said. “What now?”

Mort peered at the faded names on the spines.

“They don’t seem to be in any order!” he moaned.

They looked up. They wandered down a couple of side alleys. They pulled a few books off the lowest shelves at random, raising pillows of dust.

“This is silly,” said Mort at last. “There’s millions of lives here. The chances of finding his are worse than—”

Ysabell laid her hand against his mouth.

“Listen!”

Mort mumbled a bit through her fingers and then got the message. He strained his ears, striving to hear anything above the heavy hiss of absolute silence.

And then he found it. A faint, irritable scratching. High, high overhead, somewhere in the impenetrable darkness on the cliff of shelves, a life was still being written.

They looked at each other, their eyes widening. Then Ysabell said, “We passed a ladder back there. On wheels.”

The little casters on the bottom squeaked as Mort rolled it back. The top end moved too, as if it was fixed to another set of wheels somewhere up in the darkness.

“Right,” he said. “Give me the candle, and—”

“If the candle’s going up, then so am I,” said Ysabell firmly. “You stop down here and move the ladder when I say. And don’t argue.”

“It might be dangerous up there,” said Mort gallantly.

“It might be dangerous down here,” Ysabell pointed out. “So I’ll be up the ladder with the candle, thank you.”

She set her foot on the bottom rung and was soon no more than a frilly shadow outlined in a halo of candlelight that soon began to shrink.

Mort steadied the ladder and tried not to think of all the lives pressing in on him. Occasionally a meteor of hot wax would thump into the floor beside him, raising a crater in the dust. Ysabell was now a faint glow far above, and he could feel every footstep as it vibrated down the ladder.

She stopped. It seemed to be for quite a long time.

Then her voice floated down, deadened by the weight of silence around them.

“Mort, I’ve found it.”

“Good. Bring it down.”

“Mort, you were right.”

“Okay, thanks. Now bring it down.”

“Yes, Mort, but which one?”

“Don’t mess about, that candle won’t last much longer.”

“Mort!”

“What?”

“Mort, there’s a whole shelf!”