Sally Mullin had insisted that Nicko take her new boat, Annie.

"I hope she gives you as much luck as my Muriel did," she had said. "Just don't turn her into canoes this time."

Nicko had promised. Annie - a wide, generous boat with a cozy cabin - was far too good to turn into anything else.

After helping Jannit and Maggie to safely dock the Pig Tub, Nicko and Rupert had not set off until way past midnight. They sailed up the river, heading toward the Ramblings on the north side of the Castle. It was slow progress at first because the blustery northeast wind was against them, but they followed the river around as it hugged the Castle walls, and slowly Annie's position to the wind altered and she picked up speed.

It was a miserable journey. The eerie sight of the desolate, Darkened Castle made both Rupert and Nicko doubt that they would find anyone safe in the Heaps' room at the top of the Ramblings. And when, once again, the terrifying roar echoed across the river, they began to dread what they would find.

"What is it?" Rupert whispered.

Nicko shook his head. Right then he didn't want to know.

As they sailed toward Old Dock, a knot began to tighten in Nicko's stomach. This was the place where it was first possible to see the Heaps' tiny, arched mullion window at the very top of the Ramblings. Nicko always looked up when he passed - and felt a small tug of nostalgia for times gone by - but now he did not dare. He kept his eyes fixed on the dark water of the river because every moment he did not look was another moment of hope. A quick flurry of tiny snowflakes blew into his eyes and Nicko rubbed them away, glancing up as he did so. There was no light. The sheer wall of the Ramblings reared up like a cliff face and, just like a cliff face, it was totally dark. A wave of desolation swept over Nicko; he slumped down and stared at the tiller. It was then that he heard a splash.

"Just a duck," said Rupert in response to Nicko's questioning glance.

"Big duck," said Nicko. He stared toward the Ramblings side where the splash had come from, for some reason his hopes beginning to rise. Then came another splash and a scream cut through the air.

"Lucy!" Rupert gasped. "That's Lucy." No one screamed like his sister.

Nicko had already turned Annie toward the splashing. Rupert took the boat lamp out from under its cover and played its light across the water, searching.

"I can see her!" he shouted. "She's in the water. Lucy! Lucy! We're coming!" He threw the ladder over the side.

Beside the Underflow the stranded group heard shouts from the river and saw a light suddenly appear from the darkness. In the wildly swaying beam of light they saw Sarah being pulled from the water and then Simon's head bobbing at the foot of the ladder. A curse traveled across the water, followed by a voice saying, "It's your dingbat brother."

"Which one?" came the reply that they all recognized as belonging to Nicko.

"What does he mean, which one?" muttered Septimus.

It took a few trips in Annie's coracle to pick up Jenna, Septimus, Lucy and Marcellus. But eventually everyone was on board, a little wetter than they would have liked, but not - as Jenna pointed out - as wet as they would have been if Nicko hadn't shown up.

Nicko could not stop grinning as he hugged his brother - not the dingbat one - and his sister.

"Did Stanley tell you where we were?" asked Jenna, gratefully wrapping herself in one of the many blankets that Sally Mullin had provided.

"Eventually," said Nicko. "That rat does go on. Anyway, we decided we'd sail around and wait below. I figured sooner or later you'd look out and see us, Jen." He smiled. "Seem to remember you were always gazing out of the window when you were little."

"Good old Stanley," said Jenna. "I do hope his ratlets are okay."

"His what?"

Jenna's answer was cut short by another bleak roar echoing across the water.

"His - oh Nicko, Sep, oh - look at that . . . what is it?"

Illuminated by the glow from the Wizard Tower SafeShield, a monstrous shape could be seen inside the Darke Fog.

"It's massive . . ." Jenna breathed.

The creature opened its great mouth and sent another bellow across the river.

"It's . . . a dragon," gasped Nicko.

"About ten times bigger than Spit Fyre," said Septimus, who was feeling extremely worried about his dragon.

"It would eat Spit Fyre for breakfast," said Nicko.

"Nicko, don't!" protested Jenna.

But Nicko had voiced the very thing that was worrying Septimus.

They stared across the water, watching the monster. It appeared to be trying out its wings - of which it had six. It rose a little into the air and then fell back with what sounded like a roar of frustration.

"Six wings. A Darke dragon," muttered Septimus.

"That's not good," said Nicko, shaking his head.

Marcellus joined them. "Things are worse than we feared. No one is safe in the Castle with that thing on the loose. How fast can this boat go, Nicko?"

Nicko shrugged. "Depends on the wind. But it's blowing up a bit. We can get to the Port not long after dawn if we're lucky."

"The Port?" asked Marcellus, puzzled. He glanced at Septimus. "You have not told him, Apprentice?"

"Told him what?" asked Nicko suspiciously.

"That we're going to Bleak Creek," said Septimus.

"Bleak Creek?"

"Yes. Sorry, Nik. We have to get there. Fast."

"Jeez, Sep. Isn't it bad enough for you here? You want more Darke stuff?"

Septimus shook his head. "We have to go. It's the only hope we have to stop what's happening here."

"Well, you're not taking Mum," said Nicko.

Sarah's bat ears were working well. Her head appeared in the lighted hatch. "Not taking Mum where?"

"Bleak Creek," said Nicko.

"If that's where Septimus needs to go, then that's where I'll go too," Sarah said. "I don't want you wasting any time on me, Nicko. Just do what Septimus asks you - and Marcellus too."

Nicko looked surprised. "Okay, Mum. Whatever you say."

They sailed past the reassuringly normal lights of the Grateful Turbot Tavern and then Annie's mast scraped under the One Way Bridge, setting Nicko's teeth on edge. As they began to round the first bend, everyone gathered on deck to catch a last glimpse of the Castle. The only sound was the creaking of Annie's ropes and the swash of the water as she sailed briskly along. Her passengers were grimly silent. They looked back at the dark shape of the Castle that had been their home and thought about all the people left behind. Lucy wondered if her mother and father were still alive - How long could you survive in a Darke trance? Simon had told her he'd once been in a trance for forty days and had been okay at the end of it. But Lucy knew Simon was different. She knew he'd practiced all kinds of Darke things, even though he didn't like to talk about it. But her parents didn't have a clue about stuff like that. Lucy imagined them collapsed outside the gatehouse, snow covering them as they slowly froze. She stifled a sob and rushed below. Simon went after her.

As they drew farther away, the Wizard Tower became visible - but only just. The Darke Domaine was rising higher and only the top two floors of Marcia's rooms and the Golden Pyramid were now clear of the Fog. The indigo and purple SafeShield still shone brightly, but every now and then there was a new color visible - a faint flash of orange.

Sarah and Jenna took comfort from the lights. They thought of Silas somewhere in the Tower, adding his - admittedly small and somewhat unreliable - share of Magyk to the Wizard Tower's defenses. Septimus and Marcellus, however, took no comfort at all.

Marcellus drew Septimus away from the others. "I assume you know what that orange flash means, Apprentice?" he asked.

"The SafeShield is in distress," Septimus said. He shook his head in disbelief. "That's not good."

"No, it's not," said Marcellus.

"How long do you think we've got until it . . . fails?" asked Septimus.

Marcellus shook his head. "I don't know. All we can do is make haste to Bleak Creek. I suggest you get some rest."

"No. I'll stay up. We still have to figure out exactly where in Bleak Creek the Portal is," said Septimus.

"Apprentice, you must sleep. You have a task ahead of you for which you will need all your powers. Simon and I will do the final calculations - no protests, please. He is proving a most able mathematician."

Septimus hated the thought of sleeping while Simon took his place at Marcellus's side. "But - "

"Septimus, this is for the good of the Castle, for the survival of the Wizard Tower. We must all do what we can - and what you can do now is sleep. Come away from the Tower, it does no good." Marcellus put his arm around Septimus's shoulders and tried to steer him toward the cabin.

Septimus resisted. "In a minute. I'll come in a minute."

"Very well, Apprentice. Do not be long." Marcellus left Septimus alone and went below.

Septimus longed for a glimpse of Marcia. He wanted to see her face at the window, to know that she was all right. "Nicko, do you have a telescope?" he asked.

Nicko did have a telescope. "Tower looks good, doesn't it?" he said, handing it to him. "I like the orange."

Septimus made no reply. He focused the telescope on the Wizard Tower and silently added his own Magnification. The top of the Tower that was peeping up over the Fog sprung into sharp focus. Septimus gasped. It seemed so close that he felt he could reach out and touch it. Eagerly he searched out Marcia's study window, which he thought should just be visible. It was. And not only was the study window visible but so was the unmistakable shape of Marcia's head and shoulders, silhouetted against the lighted window. It looked as though she was staring out the window straight at him. Feeling a little silly Septimus waved, but almost immediately Marcia turned away, and Septimus knew that she had not seen him at all. Feeling suddenly lonely, Septimus longed to talk to Marcia. He longed to tell her that there was still hope, to say "hold on as long as you can. Don't give up. Please don't give up."

Jenna's voice broke into his thoughts. "Let me have a look, Sep. Please. I want to see . . . well, I want to see if I can spot Dad anywhere."

Reluctant to let go of what felt like a link to the Wizard Tower, Septimus swung the telescope upward for a quick last glance at the Golden Pyramid. He gasped in surprise. Sitting on the flattened square at the very top of the pyramid was the unmistakable shape of Spit Fyre.

"What is it, Sep?" asked Jenna, worried.

Septimus handed her the telescope with a broad smile. "Spit Fyre. So that's why he never came. Somehow he's got inside the SafeShield. He's sitting on top of the Golden Pyramid."

"Wow. So he is," said Jenna. "Clever dragon. No one can get him there."

"For now," said Septimus. He went over to the hatch. "I'm going to get some sleep, Jen."

Jenna sat on the cabin roof, playing the telescope over the few visible windows in the Wizard Tower until Annie eventually rounded the bend and the Castle disappeared from sight. But she saw no sign of Silas.

The next morning the wintry sun rose to reveal an unfamiliar landscape. On either side of the river were empty fields dusted with frost and dotted with sparse trees stretched out to a range of blue hills on the horizon. The land seemed deserted, with not a farmhouse in sight.

The inside of Annie's cabin was warm but cramped. Nicko, Jenna, Rupert and Lucy were up on deck, leaving Sarah some space in the tiny galley to prepare a huge plate of scrambled eggs for breakfast. Marcellus and Simon were at the chart table with their set squares and protractors, making their final drawings from the almanac's coded coordinates of the Portal to the Darke Halls. Septimus was still asleep, tucked into a quarter berth, with only his tangled curls visible above his cloak and one of Sally's blankets. No one was in a hurry to wake him.

Eventually the mouthwatering smell of the eggs drifted into his dreams and Septimus opened his eyes blearily.

Simon looked up, his eyes red-rimmed with fatigue. "We've figured out where the Portal is," he said.

Septimus sat up, remembering with a sinking feeling what he was going to have to do that day. "Where?" he asked.

"Have some breakfast first, Apprentice," said Marcellus. "We'll discuss it afterward."

Septimus knew it was bad news. "No. Tell me now. I need to know. I need to . . . to get ready."

"Septimus, I'm so sorry," said Marcellus. "It's in the Bottomless Whirlpool."