A large variety of animals had spent time - sometimes their whole lives - in the room behind the Big Red Door, but Thunder was the first horse. Sam had once brought a goat in but only for a few seconds. Sarah Heap did not, in those days, have things with hooves in her room. But this time Sarah had no problems with hooves. She was perfectly happy to have a huge black horse standing in the corner while her Simon fed him some withered apples that he had found in a bowl on the floor.

Sarah was amazed at the transformation of her old home. As she stood gazing about her, taking in all the changes that Silas had secretly made over the previous year, happy memories came flooding back and began to displace the heaviness and gloom that the Darkenesse had left within her. Now she understood why Silas was always disappearing.

Neither Jenna nor Simon had been back to their old home since their hurried departure on Jenna's tenth birthday, and now they hardly recognized the place. Gone were the piles of books, clutter, bedding and general household "jumble-junk," as Silas had called it. Now there were rows of neat - albeit homemade - bookshelves carrying all the Magyk books that Silas had once saved by hiding them in the attic. The fireplace in the central chimney was swept and laid with large logs; the pots hanging on the chimney were clean and lined up in order of size; the worn wooden floor was covered with rugs (some of which Jenna recognized from the Palace) and scattered with cushions, ready for the chairs that Silas was planning to make.

For Septimus it was a strange feeling to be in the very place where he had been born and yet had spent no more than the first few hours of his life. He stood awkwardly on the threshold. He saw Simon with his arm around Lucy pointing something out to her from the mullioned window that looked out over the river and Septimus realized why he felt so uncomfortable. Simon was at home; this was where he had belonged. It was he, Septimus, who was now the outsider.

Sarah Heap saw her youngest son at the doorway, looking as if he was waiting to be asked in. The sight of him cleared the very last remnants of the Darkenesse from her head. She walked over to Septimus, put her arm around his shoulders and said, "Welcome home, love." Sarah drew him inside and closed the door.

A strange feeling welled up inside Septimus - he didn't know whether he wanted to laugh or cry. But he did know that he felt like a weight he had been carrying on his shoulders without even realizing it had suddenly been lifted off. It was true - he was home.

The Longest Night drew on. Outside the Ramblings the Darke Domaine grew stronger as it spread through the Castle, drawing energy from all those trapped within it. The only spaces that remained clear were the Wizard Tower, protected by its dazzling SafeShield, the Sealed Hermetic Chamber, in which Beetle sat like a butterfly in a chrysalis, a tiny SafeChamber deep within Gothyk Grotto - and the Ramblings.

The Ramblings had been inhabited for a very long time. It went back to the days when many Castle inhabitants practiced a little amateur Magyk of their own, and so there were many remnants of SafeScreens, PassageProtectors, Blessings, HappyHomes and all kinds of spells for good things still hanging around the entrances. The Magyk was faint, but its cumulative effect over the years had soaked into the old stones and was enough to halt the Darke Domaine at every single archway, gate, door and window that led into the Ramblings. It was not, however, strong enough to hold out against the determined assault that now began.

At the ivy-covered archway near Ma Custard's - and at each and every Ramblings entrance - the ragged shadow of a Thing walked out of the Darke Domaine. The Thing stepped through the archway, forcing its way through the ancient echoes of Magyk. With it came the first tendrils of Darkenesse, smothering the rushlight with a soft hisssssss as they went swirling into the corridor. The Thing - which happened to be the one that Spit Fyre had hurled into the river - dripped along the stone flags, sending the candles sputtering out and drawing the eddying blackness behind it. As it passed by the rooms and apartments, the Darke Domaine went creeping under the doors and through the keyholes, and the fearful voices within were stilled. Sometimes there was a scream or a shout of joy as someone thought they were about to meet a long-lost love, but these were soon cut short and followed by silence.

On the top floor of the oldest part of the Ramblings, in the room behind the Big Red Door, Sarah Heap was getting ready for a siege. Against all protests she was about to go and fetch water from the Well Hall.

"I'll come with you," Septimus and Simon said at the same time - and then glared at each other.

Sarah regarded her oldest and youngest sons. "You can both come, but I'm not having you squabbling all the way to Well Hall and back," she said sternly. "Understood?"

Septimus and Simon grunted assent and then frowned, annoyed at sounding so similar.

Flanked by her oldest and youngest sons, both now taller than she, Sarah set off for the once familiar trip to the well. As she walked between them, moving swiftly along the silent passageways, she could hardly believe what was happening. It was all her dreams come true. No matter that her sons refused to speak to each other, or that terrible things were happening in the Castle right then - and no doubt would soon reach them too. She had, for a few precious minutes, her boys back. Not all her boys, it was true, but she had the very two of whom so many times she had despaired of ever seeing again - and indeed had often believed dead.

Sarah's moment of contentment did not last long. As they made their way back from the Well Hall, each carrying two heavy pails of water, they saw a telltale eddy of Darkenesse appear around the far corner of Big Bertha. Quickly they hurried into There and Back Again Row and the Big Red Door threw itself open. They rushed in and the door immediately slammed itself shut. Sarah shoved the key in the lock and turned it.

"It needs an Anti-Darke," Septimus said. "I'll do one."

Sarah didn't like Anti-Darkes. She had grown up in a family that contained both witches and wizards and she was not happy hearing the word "Darke" spoken in her home, even when it was partnered by the word "Anti." Sarah subscribed to the witch view on words - a deed named was a deed claimed. "No, thank you, love," she said. "We'll be safe without. The door has its own Magyk."

Marcellus, who had been feeling rather useless since they had arrived in the room, was glad to weigh in with some advice. "We need all the protection we can get, Mistress Heap," he said. "My Apprentice is right."

Both Simon and Sarah shot Marcellus a questioning look. "Your Apprentice?" said Sarah.

Marcellus decided not to - as Septimus would have said - go there. "I would go as far as to say that an Anti-Darke may be essential for our survival," he said.

Simon could hold back no longer. "That is true," he said. "What we need is a fluid Anti-Darke combined with a powerful SafeScreen. Once those are in place we must have an effective Camouflage - that is crucial."

Septimus gave a snort of derision. Did Simon really expect him to take the advice of the very person who had caused this whole thing to happen?

Simon misunderstood the snort. He tried to explain. "Look, you can do the most powerful Anti-Darke in the world, but it's no good if it's visible. A Darke Domaine will just hammer away at it until it's gone. And sooner or later it will be. Trust me, I know."

"Trust you?" spluttered Septimus - worried by the fact that he had actually agreed with everything Simon had said. "You must be joking."

The argument continued.

Sarah tried to ignore her sons. She wanted them to sort things out between them and she hoped that the knowledge that a Darke Domaine was coming their way would concentrate their minds. She busied herself checking all the preserved and dried food that Silas had piled up in the larder - and she told Septimus and Simon to stop bickering. She calmed Thunder by blowing on his nose and whispering to him - and she told Septimus and Simon that there was to be no arguing about anything. She began sweeping up some wood shavings that Silas had left behind - and she told Jenna to keep out of other people's quarrels. She told Lucy to let Jenna be. And then, when a full-on fight, with Jenna and Septimus on one side and Simon and Lucy on the other, seemed inevitable, Sarah's patience ran out.

"Stop it, all of you!" she yelled, banging the end of her broom on the floor. "Stop it right now!"

The melee by the door paused and they looked at Sarah, surprised.

"I will have no angry words in this room, do you understand?" Sarah told them. "I don't care what any of you have done in the past, I don't care how stupid or misguided or just plain bad you have been - and some of you have been all of those - because you are my children. All of you. And yes, Lucy, that includes you too now. Whatever any of you have done, however much you have hurt each other in the past, when you are in this room you will put that to one side. You will behave toward each other as brothers and sisters should. Is that understood?"

"Well said," murmured Marcellus.

Jenna, Septimus, Simon and Lucy looked dumbfounded. They nodded sheepishly. Simon and Lucy went and sat by the fire, leaving Septimus to do the Anti-Darke his own way, which was also, Simon noticed, his way.

Jenna went over to the window. An unusually quiet rat was sitting on the windowsill, gazing out.

"Hello, Stanley," she said.

"Hello, your Majestyness," Stanley replied with a heavy sigh.

Jenna followed his gaze to the river. Across the water the lights of the Grateful Turbot Tavern could just be seen flickering through the trees, and far below the indigo ribbon of the river flowed slowly past.

"It's clear out there," said Jenna. "Isn't it lovely? No Darke stuff."

"Only a matter of time," Stanley replied gloomily.

The flap of a wounded shoe sounded behind them. Marcellus joined them at the window. "Not so," he said. "A Darke Domaine is stopped by flowing water, especially by that which is influenced by the tides of the moon."

"Really?" said Jenna. "So . . . outside here, outside this window, will stay safe?"

Marcellus peered down. It was a precipitous drop straight down to the water's edge. "I believe so," he said. "The river runs close here."

Jenna knew all about that. She had watched the river from her own little window in her cupboard for as long as she could remember. "It comes right up to the walls," she said. "There's no bank at all, just some pontoons for boats to tie up to."

"Then there is nowhere for the Domaine to go," said Marcellus.

"In that case," said Stanley, who had been listening with great interest, "I'll be off."

"You're going?" asked Jenna.

"I must, your Majestyness. I've got four ratlets out there all alone. Goodness knows what's happening to them."

"But how're you going to get down?" Jenna looked out the window. It was a very long way down indeed.

"A rat has its ways, your Royal Personageness. Besides, I do believe I can see a drainpipe. If you'd be so kind as to open the window, I'll be off."

Jenna looked at Marcellus questioningly. "Is it safe to do that?" she asked.

"It is, Princess - for the moment at least. Of course, we do not know what will trickle down from the roof later. If the rat needs to go, it had better go now."

Stanley looked relieved. "If you'll do the honors, Sir, I'll go right away," he said.

Marcellus looked puzzled. "What honors?"

"He means open the window," explained Jenna, who had spent enough time with Stanley to be able to translate.

Marcellus pulled the window ajar and a gust of cold fresh air blew into the room.

"What are you doing?" cried Sarah, aghast. "You'll let it all in. Close the window now!"

Quickly the rat hopped onto the sill and peered down, trying to figure out the best way down the sheer rock face of the Ramblings.

"Stanley, please, could you - " Jenna began as Sarah came hurtling across the room, still holding her broom.

"Could I what?" asked Stanley edgily, eyeing Sarah with the suspicion of a rat used to trouble with brooms.

"Find Nicko - Nicko Heap, at Jannit's boatyard. Tell him what's happening. Tell him where we are. Please?"

Sarah slammed the window shut.

On the other side of the glass, Jenna saw Stanley's little rat mouth open wide in surprise as he tumbled away into the night.

"Mum!" yelled Jenna. "What are you doing? You've killed him."

"Better a rat than all of us, Jenna," said Sarah. "Anyway, he'll be all right. Rats always land on their feet."

"That's cats, Mum, not rats. Oh, poor Stanley!" Jenna peered down but she could see no sign of him anywhere. She sighed. She didn't understand her mother, she really didn't. She would happily send a rat hurtling to its doom and yet risk her life for a duck.

"He'll find something to catch hold of, Princess," said Marcellus. "Don't you worry."

"I hope so," said Jenna.

Stanley's eviction upset everyone - including Sarah. She hadn't meant for the rat to fall. In her panic to close the window, she hadn't registered the fact that Stanley was on the outside. But Sarah was not going to admit to that. She needed to keep control of things, and if people thought she was tough enough to throw out a rat to its possible demise, then that was no bad thing.

Sarah set about organizing everyone, and soon there was a fire blazing and a fragrant stew bubbling in the pot hanging above it. A stew, Lucy noted, as far removed from her mother's as to be worthy of a different name. At the thought of her mother, Lucy sighed. She hardly dared think what was happening to her parents just then - or to Rupert in the boatyard. In fact, it was all so frightening that Lucy hardly dared think at all. She sat close to Simon beside the fire and held him tight. At least Simon - bruised and battered though he was from the Fetch - was safe.

Simon drew Lucy close to him. "They'll be okay, Lu," he said. "Don't you worry."

But Lucy did worry. And so did everyone else behind the Big Red Door.