Marcia handed Septimus the numbers and then she opened The Undoing of the Darkenesse.

"Read the numbers out to me please, Septimus."

The red glow suffusing the study went out like a light. There was a collective gasp.

"SafeShield's out," Marcia said grimly.

* * *

Far below, the Barricade smashed to the ground and the first Thing walked across it, into the Wizard Tower courtyard. Twelve more followed, along with a stream of Darke Fog.

At the top of the Tower Septimus read out the first number of the first pair. "Fourteen."

With urgent fingers Marcia flipped the thick pages of The Undoing of the Darkenesse to page fourteen.

Septimus read out the second number of the first pair. "Ninety-eight."

As fast as she could Marcia began to count along the words on page fourteen until she reached the ninety-eighth word.

"Let." It seemed a very small word for all the trouble finding it.

And so, agonizingly slowly, Marcia began to put together The Great UnDoing.

Outside the Wizard Tower, on the topmost marble step, a Thing reached out a long bony finger and pushed against the tall silver doors. They swung open like shed doors left unlatched in a summer breeze. The Thing walked into the Wizard Tower and the Darke Domaine tumbled in after it. The lights went out and someone screamed. In the shadows of her tiny office Hildegarde was suddenly certain that her little brother, who at the age of seven had disappeared during a Do-or-Die exercise in the Young Army, was outside the door. She ran to open it and the Darke Fog rushed in.

Things streamed in across the threshold, bringing the Darke Domaine with them. They milled around, squashing the dying floor beneath their feet, watching Wizards and Apprentices slump to the ground. As the Darke Fog began to fill the hall, the Things wandered across to the Stopped stairs and began to climb. Behind them the Darke Domaine moved slowly up through the Wizard Tower, filling every space with Darkenesse.

At the very top of the Tower, Marcia had in her hands a piece of paper with a string of forty-nine words on it, which formed, she sincerely hoped, The Great UnDoing. She and Septimus were running up the narrow stone steps to the Pyramid Library with Alther following in their wake. They flung themselves through the little door and Marcia hurried over to the window that led outside. She turned to Septimus.

"You really don't have to come," she said.

"Yes, I do," said Septimus. "You need all the Magyk you can get."

"I know," said Marcia.

"So I'm coming with you."

Marcia smiled. "Out we go then. Don't look down."

Septimus looked neither down nor up. Focusing only on the hem of Marcia's purple cloak, he followed her up the stepped side of the golden Pyramid. Alther flew slowly behind.

And so, for the second time that night, Marcia stood on the tiny platform at the top of the golden Pyramid. For some reason, she wasn't sure why, she took off her purple python pointy shoes and stood barefoot on the ancient silver hieroglyphs that were incised into the hammered gold top. She waited for Septimus to join her and then together, in voices that cut through the Darke Fog, they began the forty-nine-word incantation of The Great UnDoing.

"Let there be . . ."

Far below, the leading Thing poked its finger lazily at the great purple door that guarded Marcia's rooms. Twelve Things stood behind it expectantly, waiting to take over their new abode. The door swung open. The Thing turned to its companions with what was possibly a smile. They stood, savoring the moment, watching the Darke Fog tumble in and swirl around Marcia's precious sofa.

At the top of the golden Pyramid, Marcia Overstrand, ExtraOrdinary Wizard, and her Apprentice, Septimus Heap, spoke the last word of The Great UnDoing.

With a great crash Marcia's door slammed in the Things' faces. A loud whirring ensued - the door Barred itself and, for good measure, sent out a Shock Wave. Thirteen Things screamed. A scream of thirteen Things is not one of the most harmonious sounds, but to Septimus and Marcia, teetering at the top of the golden Pyramid, it was the sweetest thing they had ever heard.

And then they saw the most beautiful sight they had ever seen - the Darke Fog rolling away. Once more they saw the Castle they loved - its higgledy-piggledy roofs, its turrets and towers, its crenulated battlements and tumbledown walls, all outlined against the pink sky of the dawn of a new day. And as they watched the sun rise, dispelling the shadows that lurked below, the first heavy snowflakes of the Big Freeze began to fall. Marcia and Septimus smiled at each other - the Darke Domaine was no more.

Some minutes later, a broadly smiling Marcia was ushering everyone into her sitting room, busily opening the windows to get rid of the dank smell of the Darke. Jim Knee was curled up in his usual place on the sofa with Jillie Djinn beside him, just as Marcia had left them. But there was something about the Chief Hermetic Scribe that made Marcia hurry over to her.

"She's dead!" Marcia gasped. And then, much more dismayed, she cried, "She's dead on my sofa!"

Jillie Djinn was slumped backward, mouth a little open, eyes closed as if asleep. Her body was there, but she herself had clearly gone - whatever it was that had been Jillie Djinn was no more. The Great UnDoing had been her undoing also.

Chapter 48 Restoration

Marcia, Septimus and Jenna emerged from the Great Arch and paused for a moment, looking down the newly liberated Wizard Way. It was a beautiful frosty morning. The sun was creeping out from behind a bank of clouds and slanting rays of the early morning light glanced low along Wizard Way. The first serious snowflakes of the Big Freeze were beginning to fall; they drifted lazily in the fleeting sunlight and settled onto the frosty pavement.

Marcia took a deep breath of the clear, sparkling air and a wave of happiness very nearly overcame her - but she could not allow herself to be completely content until she had successfully UnSealed the Hermetic Chamber. And found Beetle alive.

Marcia had steeled herself to expect many things waiting for her in the front office of the Manuscriptorium but she had not expected the Port Witch Coven. They had taken a trip to see the last moments of the Wizard Tower and, becoming bored with how long it was taking, they had crowbarred the planks off the door to the Wild Book and Charm Store. They were just emerging, covered in fur, feathers and a light sprinkling of scales when, to their collective horror, they saw that not only had the lovely Darke Fog disappeared but that that ghastly ExtraOrdinary Wizard woman was waiting for them. Dorinda's piercing scream spoke for them all.

To Jenna's delight, Marcia saw the Port Witch Coven off the premises with great effectiveness. They left so fast - even the Witch Mother managed a rapid hobble in her spikes - that they forgot about Nursie, who sat unnoticed beside a collapsed pile of books. Nursie had discovered a stash of dusty licorice snakes in the back of a drawer and was contentedly chewing them. Nursie had what she called a penchant for licorice.

Marcia raced into the Manuscriptorium itself, closely followed by Jenna and Septimus. The place was strewn with upturned desks, ripped paper and broken lamps. Everything was covered with a sticky gray dust, which Septimus realized to his disgust was shed Thing skin. Quickly they picked their way through the debris. At the stone arched entrance to the Hermetic Chamber they stopped.

"The Seal is gone," Marcia said heavily. "I fear the worst."

The seven-cornered passage looked ominously well used - there was a slimy Thing trail on the floor. Like giant slugs, thought Septimus. He stepped into the passage and called tentatively into the dark. "Beetle . . . Beetle." There was no reply.

"It sounds . . . dead in there," he whispered.

"I think," said Jenna slowly, "that it sounds more like something is blocking the passageway farther up."

"It is just possible that the Seal is still holding farther in," said Marcia.

"Can it do that?" asked Septimus. "I thought it would all go at once."

"We'll just have to see, won't we?" Marcia said briskly and she disappeared into the seven-cornered passage. Septimus and Jenna set off after her.

As he rounded the sixth corner, Septimus cannoned into Marcia. "Oof!"

Marcia was standing at a dead end of pitted stone. "It's still Sealed," she whispered excitedly. "It really is quite amazing. The Seal has been chipped away but I think . . . I think it's still okay."

"Does that mean that Beetle is . . ." Septimus could not finish his question. The thought that Beetle might not be okay made him feel sick.