Gudrun the Great was guarding the Palace Gate. She was floating a few feet off the ground and dozing peacefully in the sunshine.

Gudrun, an Ancient ghost who was one of the very early ExtraOrdinary Wizards, was dreaming of the old days when the Wizard Tower was new. She was almost invisible in the bright sun, and Jenna and Septimus were so busy discussing the mysterious horseman that they walked straight through her. Gudrun the Great nodded dreamily to them, mistaking them for a pair of her own Apprentices from long ago, who had been twins.

The year before, Alther Mella had taken over the task of running the Palace and the Castle until the Time was Right for Jenna to be Queen. He had decided that, after ten years of the hated Custodian Guards stomping up and down in front of the Palace and terrorizing the population, he never wanted to see soldiers guarding the Palace again. So Alther, a ghost himself, had asked the Ancients to act as guards. The Ancients were elderly ghosts; many of them were at least five hundred years old, and some of them, like Gudrun, were even older than that. As ghosts become more transparent with age, most of the Ancients were quite hard to see. Jenna was still not used to walking through a doorway and discovering that she had also walked through the dozing Second Keeper of the Queen's Bedpost or some such ancient dignitary. She would only realize her mistake when she heard a quavery voice wishing her, "Good morn to thee, fair maiden," as the trodden-upon Ancient suddenly woke up and tried to remember where he or she was. Luckily the Palace had not changed much since it had been built, so most of the Ancients could still find their way around. Many of them were old ExtraOrdinary Wizards, and the sight of a faded purple cloak flitting through the maze of endless corridors and rooms at the Palace was not unusual.

"I think I just walked through Gudrun again," saidjenna. "I hope she didn't mind."

"Well, I still think it's odd having ghosts guarding the gates," Septimus replied, looking at his thumb, which seemed all right again, much to his relief. "I mean anyone could just walk in, couldn't they?"

"That's the idea," saidjenna. "Anyone can walk in. The Palace is here for everyone in the Castle. It doesn't need guards to keep people out anymore."

"Hmm," said Septimus. "But there might be some people you still need to keep out."

"Sometimes, Sep," said Jenna, "you get too serious for your own good. You spend far too much time cooped up in that smelly old Tower, if you ask me. Race you!"

Jenna ran off. Septimus watched her as she raced across the lawns that spread in front of the Palace, dusty and brown in the midsummer heat. The lawns were long and wide and were cut in two by the broad drive, which swept up to the entrance of the Palace itself. The Palace was one of the oldest buildings in the Castle; it was built in the ancient style, with small, fortified windows and battlements running along the top of the walls. In front of it was a shallow ornamental moat that was home to some fearsome snapping turtles left by the previous occupant, the Supreme Custodian, which were almost impossible to get rid of. A broad, low bridge spanned the moat and led to a pair of heavy oak doors, which were thrown open in the early-morning heat.

Septimus liked the Palace now. It was a welcoming building with its yellow stone glowing warmly in the sun. As a boy soldier he had often stood guard outside the gate, but then it had seemed a dark, gloomy place, occupied by the dreaded Supreme Custodian. Even so, Septimus had never minded standing guard, for although it was often boring and cold, at least it was not frightening like most of the things he had had to do in the Young Army.

In the summer Septimus would watch Billy Pot, the Lawn Cutter, who had invented a Contraption. The Contraption was meant to cut the grass. Sometimes it did and sometimes it didn't, depending on how hungry the occupants of the Contraptionthe lawn lizardswere. The lawn lizards were Billy's secretor at least he thought they werealthough most people had figured out how the Contraption worked. And when it worked it was simple: Billy pushed the Contraption along and the lizards ate the grass. When it didn't work, Billy lay down on the grass and yelled at them.

Billy Pot kept hundreds of lawn lizards in lizard lodges down by the river, and every morning he would select the twenty hungriest lizards, put them into the cutting box at the front of the Contraption and wheel them off to the Palace lawns. Billy hoped that one day he would actually finish cutting the lawns before it was time to start all over again; he would have liked to have a day off now and then. But this never happened. By the time he had pushed the Contraption across the huge expanse of grass and the lawn lizards had done their job, it was time to start all over again.

As Septimus set off across the grass, trying to catch up with Jenna, who was far ahead of him, he heard the familiar clanking sound. A moment later Billy Pot appeared in the distance, pushing his Contraption across the broad path that ran in front of the Palace moat, slowly heading for the new day's patch of grass. Septimus speeded up, determined not to let Jenna get too far ahead. But she was bigger and faster than he was, even though they were exactly the same age. She had soon reached the bridge.

Jenna stopped and waited for Septimus to catch up. "Come on, Sep," she said. "Let's go and find Mum."

They walked over the bridge and arrived at the Palace doorway. The Ancient at the doors was awake; he was sitting on a small gold chair, placed carefully to catch the sun, and had been watching Jenna and Septimus's approach with a fond smile. He smoothed down his purple cloak, for he too had been a much-respected ExtraOrdinary Wizard in his time, and smiled at Jenna.

"Good morning, Princess," said the ghost, his thin voice sounding as though it came from a great distance. "How nice to see you. And good morning, Apprentice. How is the Transforming going? Have you managed the Transubstantiate Triple yet?"

"Almost." Septimus grinned.

"Good lad," said the Ancient approvingly.

"Hello, Godric," said Jenna. "Do you know where Mum is?"

"As it happens, Princess, I do. Madam Sarah told me that she was going to the kitchen garden to pick some herbs. I told her that the Kitchen Maid would do that for her, but she insisted on going herself. Wonderful woman, your mother," said the Ancient wistfully.

"Thank you, Godric," said Jenna. "We'll go and find herhey, what?" Septimus had grabbed her arm.

"Jenlook," he said, pointing to a dust cloud approaching the Palace Gate.

The Ancient, still in a sitting position, floated up from his chair and hovered in the doorway, peering out into the sunlight. "A Darke horse. And a Darke rider," his voice echoed thinly.

Septimus pulled Jenna into the shadows behind the ghost.

"What are you doing?" Jenna protested. "It's only that horse we saw before. Let's see who the rider is."

As she stepped out into the light of the doorway, Jenna saw the horse approaching. The rider rode the horse hard, sitting forward on the animal and urging it on, his dark cloak streaming out behind him. The horse did not stop at the gate, but carried straight on through Gudrun the Great and thundered up the driveway. Unfortunately Billy Pot was still on his way to his patch of grass. He had just started to push the Contraption across the drive when he and the Contraption were forced to make a swift change of direction to avoid the oncoming horse. Billy made it but the Contraption was not so lucky. Unused to doing anything quickly, it fell to pieces where it stood. The lawn lizards ran off in all directions, and Billy Pot found himself gazing at a pile of metal in the middle of the Palace drive.

The horseman thundered on, oblivious to Billy Pot's loss and the lizards' newfound freedom. The horse's hooves kicked up the midsummer dust and beat with rhythmic hollow thuds against the dry ground as it rapidly approached the Palace.

Jenna and Septimus waited for the horseman to take the usual path around to the stables at the back of the Palace, but to their surprise the rider ignored it and spurred the horse on over the bridge. Expertly, without breaking the horse's stride, the horseman galloped over the threshold of the door and rode straight through Godric. Jenna felt the damp heat of the horse as it passed close, letting go a long fleck of horse spittle, which landed on her tunic. She turned to protest to the horseman, but he was gonecantering across the hall at full speed. With his horse's hooves skidding on the stone flags and sending up sparks, he executed a sharp left turn into the gloom of the Long Walk, the mile-long corridor that ran down the middle of the Palace like a backbone.

Godric picked himself up from the floor and muttered, "A coldness ... a coldness went through me." He subsided shakily back into his chair and closed his transparent eyes.

"Are you all right, Godric?" Jenna asked, concerned.

"Yes, indeed," murmured the old ghost faintly. "Thank you, your honor. I mean, thank you, your Princess."

"Are you sure you're all right?" Jenna peered at the ghost but he had fallen asleep.

"Come on, Sep," whispered Jenna. "Let's see what's happening."

The inside of the Palace was dark after the brilliant sunshine. Jenna and Septimus ran across the central hallway to the Long Walk. They stared down the seemingly endless, dimly lit expanse, but there was no sight or sound of the horseman.

"He vanished," whispered Jenna. "Maybe he was a ghost."

"Funny sort of ghost," said Septimus, pointing to some dusty hoofprints on the faded red carpet that was laid on the huge old flagstones. Jenna and Septimus turned down the east wing of the Walk and followed the hoofprints. Once, before the Supreme Custodian had taken over the Palace, the Long Walk had been full of wonderful treasurespriceless statues, rich hangings and colorful tapestriesbut now it was a dusty shadow of its former self. During his ten years of occupation, the Supreme Custodian had stripped all the most valuable possessions from the Palace and sold them to fund his lavish banquets. Now, Jenna and Septimus walked past a few old paintings of previous Queens and Princesses, which had been rescued from the basement, and some empty wooden chests with broken locks and wrenched hinges. After three Queens, all of whom looked somewhat bad-tempered, and a cross-eyed Princess, the hoofprints made a sharp right turn and disappeared through the wide double doors of the Ballroom. The doors were already thrown open, and Jenna and Septimus followed the hoofprints in. There was no sign of the horseman.

Septimus let out a low whistle. "This place is big," he said.

The Ballroom was indeed huge. When the Palace had been built it was said that the entire population of the Castle could have fit inside the Ballroom. Although this was no longer true, it was still the biggest room that anyone in the Castle had ever seen. The ceiling was higher than a house and the massive windows, which were full of small panes of stained glass, stretched from floor to ceiling and threw an array of rainbow colors across the polished wooden floor. The lower panes of the windows were thrown open in the heat of the summer morning. They led out onto the lawns at the back of the Palace, which swept down to the river.

"He's gone," said Jenna.

"Or Disappeared," muttered Septimus. "Like the Ancient said, 'a Darke horse and a Darke rider.' "

"Don't be silly, Sep. He didn't mean it like that," said Jenna. "You've spent too long at the top of that Tower with a spooked Wizard and her Shadow. Anyway, he's only just gone out through that windowlook."

"You don't know that for sure," Septimus objected, stung at being called silly by Jenna.

"Yes, I do," said Jenna, pointing to the pile of horse dung steaming on the step. Septimus made a face. Carefully they stepped out onto the terrace.

It was then that they heard Sarah Heap scream.