Septimus soon found himself squashed between the two ghosts at a long table at the far end of the tavern. This was not what he had expected when he had gone to bed that evening, but after eighteen months as Apprentice to Marcia, Septimus had learned not to expect anything - except the unexpected.

Although Septimus knew he was not really squashed at all, he still felt squashed as he sat between Alther and Queen Etheldredda and tried not to touch either of them - but he could not shake the feeling that Queen Etheldredda's pointy elbows really were sticking into him. Septimus wriggled farther away from Etheldredda, for it was the height of rudeness to Pass Through a ghost and he suspected that the Queen would have something to say about it.

In fact, so far Queen Etheldredda had had something to say about pretty much everything. She sat tall and erect, and her dark violet eyes fixed Septimus with a stern gaze as she gave him the benefit of her opinion: "It's full of riffraff here, Apprentice, absolutely full. Look at that awful old tramp snoring under the table. Terrible place, terrible place. I shall most certainly have to do something about this. And the behavior of those young Queens over there - most unbecoming." A loud squeal of giggles had erupted from a table of four young Queens (all of whom had died in childbirth). Queen Etheldredda pursed her lips disapprovingly. "I don't know what Alther Mella is thinking of bringing you here. In my day the ExtraOrdinary Apprentice was not allowed out without a chaperone Wizard, and then it was only to come to the Palace on official business. And a boy your age should be in bed, not carousing in a den of iniquity like this."

Septimus was not bothered by Queen Etheldredda for she reminded him a little of Marcia, but Alther looked irritated. "Your Majesty," Alther said huffily," "perhaps you might remember that it was on your express wish - command was the word you used - that I woke up this young Apprentice and brought him here. You had, you said, something of great importance to relate to him - a matter of life or death - although you refused to tell me what it might be. You yourself insisted on him coming to this tavern. I assure you, Madam Marcia Overstrand does not normally allow her Apprentice to frequent taverns at night or, indeed, at any time of the day."

Septimus held his breath. What was the Queen going to say?

Queen Etheldredda said nothing for some time. And then she leaned over to Septimus, and he felt an ice-cold breath across his cheek as she whispered in his ear, "Marcellus Pye, at Snake Slipway, midnight. Be there." With that, the Queen got up from the tavern bench as if rising from her throne. She swished her train into place behind her, walked, head held disdainfully high, into the fireplace and disappeared.

"Well," spluttered Alther. "Of all the nerve..."

"Marcellus Pye?" Septimus muttered, feeling a thrill of excitement.

Two nuns had sat down beside him in Queen Etheldredda's place. One of the nuns looked askance at Septimus. "Do not speak that name lightly, child," she whispered.

Septimus said no more, but his thoughts were buzzing. Why would the ghost of Marcellus Pye want to meet him - just a lowly Apprentice? After all, the ghost had never been seen before. Maybe ... Septimus shivered at the thought ... maybe the ghost had been Watching him read the notes that afternoon and had now decided to Appear to him. But why choose Snake Slipway? And why at midnight?

Alther noticed Septimus's preoccupied expression. "What did she say?" he whispered.

Septimus shook his head, not wanting to upset the nuns again.

Suddenly Alther felt weary. "Come on then, Septimus, let's go." He sighed. He got up and Septimus followed him, carefully squeezing past the nuns. Alther felt unsettled at the sudden appearance of Queen Etheldredda. She had not been seen around the Palace before, and while it was not unusual for ghosts to appear and disappear, especially the older ones who often fell asleep in a comfortable chair and did not wake for many years, he had never known one to turn up so many centuries after her entry into ghosthood. It was very odd, and there was, thought Alther, something particularly odd about Etheldredda. He wished now that he had not brought Septimus to see her.

Carefully Septimus followed Alther and made his way toward the exit, which was indeed a hole in the wall, through which he could now see moonlight shining. There was a lull in the ghostly chatter as the living Apprentice to the ExtraOrdinary Wizard slipped through the assorted throng. Some stepped back to allow Septimus to pass and continued their conversations; others stopped their chatter in mid-sentence and followed his progress with faded, ghostly eyes. Some expressions were wistful, remembering what it had been like to be a living, breathing eleven-year-old; others were vague, lost in their ghosthood and seeing living beings as strange creatures, unrelated to them. But not one of the ghosts was Passed Through by Septimus as he negotiated his way around them. At last he pushed his way through the bush and reached the outside of the tavern with a feeling of relief.

"So what did she say?" Alther asked again. He and Septimus were taking a shortcut through Drapers Yard, a small courtyard around which was a cluster of old houses inhabited by families who worked with cloth. A few candles shone from the windows, which sported a strange variety of curtains and cloth remnants, but the doors were locked and barred, and the yard was so quiet that Septimus could hear the ticking of the Great Draper Clock in the clock tower above the central house.

"She said I should meet Marcellus Pye on Snake Slipway. Tonight," Septimus told him as the Draper Clock began to strike ten and its tinny bell echoed around the yard. Pling, pling, pling...

"You will of course be doing no such thing," declared Alther once the clock had stopped and the succession of comical tin figures had done their party pieces and filed back inside. "She's bonkers, Septimus, totally and utterly bonkers. Anyway, I've never even seen the ghost of Marcellus Pye. The trouble is, every now and then a ghost gets delusions of grandeur. Often happens to Royal ghosts. They think they can influence the living. Make things happen, just as they were used to doing when they were alive. Of course all they do is make a nuisance of themselves. Can be almost impossible to get rid of, that's the trouble. The best thing is to ignore them and hope they'll go away. Which is exactly what you must do, lad. I suppose you know who this Pye fellow was?"

"Yes," said Septimus.

Alther nodded approvingly. "Thought you would. It's good to read about the subject. Best not to let on to Marcia though. She has a thing about Alchemie."

"I know," Septimus sighed.

"He wasn't just an alchemist, Marcellus; he was a good physician, too," said Alther. "Pity we've lost some of the things he knew back then. We could use them now."

They were now walking briskly along Brindle Byway, which would lead them to Wizard Way. Brindle Byway was a narrow street with tall drying lofts for yarn and fabric on either side. The drying lofts were dark and quiet at this time of night and a chokingly unpleasant smell of dye hung in the still air. Septimus was too preoccupied with holding his nose and breathing through his mouth to hear, some way ahead, the scrabble of claws and the click of a needle-sharp tooth as it flicked down, ready to bite.

Neither Septimus nor Alther noticed two round red eyes emerging from a drain, blinking and shrinking from the light from the silver torch post outside Number Thirteen Wizard Way. But they did hear something altogether louder and more insistent: hurried footsteps echoing off the walls of the byway, coming toward them.

Alther glanced at Septimus and gestured to a small opening between two drying lofts. In a moment both he and Septimus were hidden in the shadows, listening to the approaching footsteps.

"Probably some pickpocket up to no good," whispered Alther. "He'd better not try anything, I'm not in a good mood this evening."

Septimus did not reply. The footsteps had slowed down now; they sounded almost hesitant as they approached the gap where Alther and Septimus were hidden. Then the footsteps stopped.

Suddenly, to Alther's horror, Septimus jumped out.

Sarah Heap gave a piercing scream and dropped her basket with a crash. Bottles and jars tumbled out and rolled in all directions.

"Mum!" said Septimus. "Mum, it's only Alther and me."

Sarah Heap stared at them in disbelief. "What on earth are you doing here? Really, Septimus, you nearly gave me a heart attack. And what does Alther think he's doing bringing you down these ghastly alleyways at this time of night?"

"It's all right, Mum. We're on our way back now. We only went to the Hole in the Wall Tavern," Septimus explained, chasing after the dropped bottles and jars and putting them back into Sarah's basket.

"A tavern?" Sarah Heap looked horrified. "Alther took you to a tavern - at night? Alther" - this was addressed to the ghost who had just floated out of the alleyway, looking resigned to the evening rapidly going from bad to worse - "Alther, what do you think you are doing? And with all this Sickenesse about?"

Alther sighed. "I'll explain tomorrow, Sarah. Although I could ask the same of you. What exactly are you doing scurrying down a back alley with all your potions?"

Sarah did not answer. She was too busy checking whether any of her potion bottles had broken. "Thank you, Septimus," she said as he handed her the last bottle.

"But where are you going, Mum?" asked Septimus.

"Going?" Sarah Heap looked as if she had come down to earth with a bump. "Oh, heavens, I'll be late. I don't want to keep Nicko waiting - "

"Nicko?" asked Septimus, confused.

"Sarah," said Alther, "what is going on?"

"I've been called to the Infirmary, Alther. I must have had the last Message Rat in the Castle. They've had so many people brought in this evening they can't cope. Nicko's going to row me over. Now I must get going."

"Not on your own," said Alther. "We'll come with you."

Sarah looked as though she was about to protest but then she changed her mind. "Thank you, Alther," she said. "I - oh my goodness!" Sarah stifled a scream. "Look..." she whispered, pointing into the darkness.

Septimus looked. At first he saw nothing and then, as he shifted his gaze, he saw them - the red eyes, moving toward them, dodging from side to side. At first glance Septimus thought it was a rat, but there was something about the way the eyes were set, both looking forward, that looked wrong for a rat's eyes. Quickly Septimus reached into his pocket, took out a pebble and sent it spinning through the darkness toward the red pinpoints. A high-pitched yelp was followed by the sound of scuffling leaves, and the eyes disappeared into the night.

"Come on, Sarah," said Alther, "let's get you down to the boatyard."

Nicko was waiting anxiously beside a rowboat tied up to the quay in Jannit Maarten's boatyard. Jannit had recently taken Nicko on as Junior Apprentice, and he now slept in a small cabin at the back of Jannit's ramshackle hut. An hour ago, Nicko had tumbled into bed, tired out after a long day helping Rupert Gringe repair the huge rudder belonging to the Port barge. He had only just fallen asleep when an insistent knocking on his window had jarred him awake - it was the Message Rat that Sarah had forwarded to him.

Quickly Nicko had found the rowboat that Jannit sometimes used to ferry people over the river; unfortunately he had woken Jannit, who even in her sleep could hear any unusual sound in the boatyard. Jannit had only just grumpily gone back to bed when she was woken again by the clinking of Sarahs bottles in her basket as she hurried through the boatyard.

Septimus helped Nicko steady the rowboat while Sarah clambered in. "You'll make sure Mum gets to the Infirmary okay, won't you, Nik?" he asked, looking doubtfully across the Moat, which was wide and deep by the boatyard, to the dim lights of the Infirmary, almost hidden under the outlying trees of the Forest some distance away. It was a dangerous walk from the ferry landing stage to the Infirmary at night.

"Of course I will." Nicko took up two long oars and waited for Sarah to get settled.

"Don't worry, I'll see Sarah to the Infirmary door," Alther said to Septimus. "I can still get rid of the odd wolverine if I have to. I'll have to whiz around by the North Gate, but I'll be there waiting for her."

"See ya later, Sep," said Nicko as he pulled away from the boatyard landing stage.

"No, you won't, Nicko," Septimus heard Sarah chide. "Septimus is going straight back to Marcia's."

As Septimus watched Alther fly toward the North Gate, a wonderful sense of freedom and exhilaration suddenly swept over him. He could go anywhere, do anything. There was no one to stop him. Of course he should go back to the WizardTower, but he was not sleepy. Septimus felt restless, as if somehow the night was unfinished. And then he realized why. Queen Etheldredda's words came back to him: "Marcellus Pye, at Snake Slipway, midnight. Be there."

Suddenly, Septimus knew why Queen Etheldredda had asked him to meet the ghost of Marcellus Pye: to give him the formula for the antidote to the Sickenesse.

It was only about half past ten. He still had time to get to Snake Slipway before midnight.