Bleak Creek was a dank and dismal place. Haunted by the ghost of the Vengeance, a Darke ship once berthed there, its waters lay deep and still, trapped between two rocky hillsides. A few stunted trees halfheartedly clung to the gaunt slopes but most had stopped bothering and had fallen into the water, where they lay rotting, providing a perfect breeding ground for the infamous Bleak Creek water snake - a nasty black squidge of venomous slime - and its equally lovely parasite, the Long White Leech. In the summer swarms of biting gnats patrolled the banks of the creek, but in the winter they were gone, thankfully. Their absence was more than compensated for by the tiny Jumping Log Beetles, which ventured onto the land once the water grew cold. Log Beetles could jump as high as six feet and would fasten their pincers into any flesh they could find and begin to chew. The only way to remove them was to snap their heads off and wait for the pincers to die. Some heads could keep chewing for days until they fell off.

Dotted among the sharp rocks that littered the hillsides were a few stone hovels built by ancient hermits, misfits and the odd person who had wanted a house by the water but had clearly suffered from a total lack of common sense. These piles of stones were deserted now, although Septimus knew that at least one was Possessed.

Not surprisingly Bleak Creek did not receive many visitors, although this was not necessarily due to its ghostly ship or even to the hostile wildlife and the pungent smell of decay that hung in the air. It was because its entrance was guarded by the notorious Bottomless Whirlpool.

Every Castle child knew the story of the Bottomless Whirlpool. How it was created during a great battle between two Wizards in ancient times; how it was said that each Wizard had stirred up the waters into a frenzy in an effort to drown the other; that they had circled one another, faster and faster, until they had both been sucked into the depths and were never seen again. Everyone knew that the whirlpool went down into the very center of the earth, and some believed that it went right out to the other side.

There were occasional day trips from the Castle to see the Bottomless Whirlpool. These were often a thirteenth-birthday present. After sailing into Bleak Creek to try and spot the Vengeance, the boats - full of new teens screaming with excitement - would circle the whirlpool. However, these trips were run by experienced skippers who knew the safe distance from the whirlpool and who could tell the early warning signs that a boat was being dragged toward it. It was only the biggest, heaviest ships - as the Vengeance had once been - that could pass close by.

Nicko knew for sure that Annie was not one of these. He also knew that he was not one of those skippers who understood the safe distance from the whirlpool, although he hoped that he could tell the signs that they were being dragged too close. And so, as the forbidding rocky outcrops that heralded the entrance to Bleak Creek came into view, Nicko began to feel nervous - but not as nervous as Septimus.

Septimus was sitting alone in the prow of the boat, just behind the bowsprit and its large red sail that billowed in the wintry wind. He had never - not even on the Do-or-Die Night Exercises in the Forest - felt so scared. He glanced down at a small sheet of paper covered with Marcellus's neat handwriting that set out some bullet-pointed questions and answers, which he was trying to fix in his head. They were not unlike the Young Army Pre-Exercise Pointers (or PEPs) that the boys had had to memorize and then chant before each expedition. This sense of deja vu added to Septimus's feeling of doom, but it also meant that he fell back into his old Young Army ways of focusing on survival - and nothing else. And so, as he sat behind the bowsprit, Septimus gazed out at the iron-gray water and chanted under his breath, learning the responses he must use when challenged by anything Darke.

"Who be you? Sum."

"How be you? Darke."

"What be you? The Apprentice of the Apprentice of the Apprentice of DomDaniel."

"Why come you here? I seek the Apprentice of DomDaniel."

Septimus was so absorbed that he did not notice Jenna and Nicko slipping into the spaces on either side of him. They waited patiently until he had stopped muttering and then Jenna spoke.

"We are coming with you," she said.

Septimus looked shocked. "What?"

"Nik and I . . . we have decided to come with you. We don't want you to go alone," said Jenna.

This had the opposite effect from what Jenna had intended - Septimus suddenly felt totally alone. He realized that they had no idea about the utter impossibility of their request. He shook his head.

"Jen, you can't. It's not possible. Believe me."

Jenna saw the look in Septimus's eyes. "Okay . . . I believe you. But if we can't come with you, then I at least want to know where you are going. Marcellus knows, even Simon knows, so I think Nik and I deserve to know too."

Septimus did not reply. He stared out at the water and wished that Jenna and Nik would leave him alone. He needed to disconnect.

But Jenna would not let him. She reached beneath her witch's cloak, took out The Queen Rules and opened it to a page she knew well. She thrust it under Septimus's nose.

"Look," she said, stabbing her finger at a grubby, well-worn paragraph.

Reluctantly Septimus squinted at the tiny type. Then he gave in. He got out his birthday present from Marcia and moved the Enlarging Glass across the page. He read:

"The P-I-W has a Right To Know all facts pertaining to the security and wellbeing of the Castle and the Palace. The ExtraOrdinary Wizard (or, in absentia, the ExtraOrdinary Apprentice) is required to answer all the P-I-W's questions truthfully, fully and without delay."

With his head full of what he had to do, Septimus didn't immediately recognize what he was looking at - and then it came back to him. He remembered the morning of his birthday, which seemed so far away now. He smiled as he recalled Marcia's comment about "the wretched red book with its tiddly-squiddly type, the bane of every ExtraOrdinary Wizard's life." So this was what she had meant. And in remembering the Wizard Tower and the Castle as it had been, and with Marcia's beautiful birthday gift in his hand, Septimus somehow felt less alone. He felt part of everything once more and he also, he realized, felt relieved. He wanted to tell Jenna where he was going, he wanted her to be part of what he was doing. Even though she couldn't come with him, she could be thinking of him while he was there, wishing him safely through the Darke Halls to the other side. Septimus wasn't sure that he should be telling Nicko too, but he no longer cared about should or shouldn't.

And so, as they drew near to Bleak Creek and they saw the telltale chop of the water that heralded the Bottomless Whirlpool, Septimus told Jenna and Nicko how he was going to find Alther and bring him back to the Castle through Dungeon Number One. He told them not to worry because he had the Darke Disguise. And even though he didn't believe it, he told them that he would be fine and he would see them soon. When he had finished talking, Nicko and Jenna were silent. Jenna wiped her eyes with her sleeve and Nicko coughed.

"We'll be there waiting, Sep," said Jenna.

"Outside Dungeon Number One," said Nicko.

"No. You can't do that."

Jenna put on her best Princess voice. "Nicko and I will be waiting for you at the entrance to Dungeon Number One. No, don't say anything, Sep. We can get through the Darke with my witch's cloak. You are not in this alone. Got that?"Septimus nodded. He did not trust himself to speak.A shout from Rupert broke the moment. "Nik - she's beginning to go!"Nicko leaped up. He could feel the pull of the current beneath them and the flapping of Annie's sails told him that the boat's prow was being pulled into the wind and she was losing way - they were heading toward the wisp of spray that marked the Bottomless Whirlpool. Nicko raced back to the stern. He grabbed the tiller from Rupert - who was not a natural sailor - and yelled, "Oars! Everyone, get the oars!"Annie's four long oars were snatched off the roof. Standing along the sides of the boat, Sarah, Simon, Lucy and Rupert dug them into the water. Frighteningly slowly, the boat's progress toward the Bottomless Whirlpool halted.Septimus got to his feet. "I have to go, Jen," he said. "I'm putting everyone at risk.""Oh. Oh, Sep."Septimus hugged Jenna and quickly stepped back. "That witch's cloak is really . . . zingy. It buzzes when I touch it."Jenna was determined to be positive. "Good. That means it's full of, er, witch stuff. It will get me and Nik through the Castle.""Right." Septimus forced a smile. "I'll see you there, then.""At the door to Dungeon Number One. We'll wait for you. We'll be there, I promise.""Yeah. Okay. I'll go and find Marcellus now.""Yep. See you, Sep."Septimus nodded and picked his way back along the deck, past Simon and Lucy, who were sitting like gloomy seagulls on the cabin roof."Good luck, Sep," said Lucy."Thanks."Simon held out a small, black metallic Charm. "Take it, Septimus. It will guide you through."Septimus shook his head. Right then it was hard to turn down any offer of help, even from Simon. But he was determined. "No thanks. I don't take SafeCharms from anyone.""Then take some advice - always take the left."Septimus reached the cockpit of the boat, where Marcellus had just emerged from the cabin."It is time, Apprentice," Marcellus said, with an anxious glance at Sarah. He had just had a fraught conversation with her, trying to impress upon her how she must let Septimus go without upsetting him. He wasn't sure that Sarah was going to manage it.But Sarah did - just. She enveloped her youngest son in a desperate hug. "Oh, Septimus! Be careful.""I will, Mum," said Septimus. "I'll see you soon. Okay?""Okay, sweetheart." With that Sarah rushed down into the cabin.Nicko and Rupert hauled the little coracle down from the mast and dropped it over the side, hanging on to its rope. The flimsy round boat made of willow and skin bobbed lightly on the water like a leaf. Aware that everyone - except Sarah - was watching him, Septimus gave a tight smile and climbed down the ladder into the coracle. Nicko handed him the single paddle. "Okay?" he said hoarsely.Septimus nodded.With every instinct telling him that he was killing his little brother, Nicko threw the rope into the coracle and set it free. At first it drifted aimlessly, bobbing merrily as if out for a summer's day paddle on a gentle lake. And then it began to turn, slowly at first, as though it had caught a gentle breeze. Moving steadily toward the wisp of steam at the center of the whirlpool, the coracle began to pick up speed and, like a fairground ride from which there is no return, to spin ever faster as it was drawn inexorably toward the edge of the vortex.And then it reached the point of no return. With a suddenness that drew a gasp of dismay from everyone on Annie, it was whirled into the slipstream of the vortex. Spinning like a top as it raced around in ever decreasing circles, Septimus's green cloak was the pivot around which his tiny black craft spun. There was a final acceleration as it tipped into the center of the whirlpool and was gone.The creek was still. Annie was silent. No one could believe what they had just done.