With great relief, Sir Hereward had watched Marcia and Alther set off down the wide corridor, take a right turn at the end and disappear from sight.

Behind the doors of Jenna's bedroom, another, altogether more unpleasant ghost took her ear from the door, a smile playing across her thin lips. So the troublesome young Princess had run off to the Marram Marshes with the Apprentice, had she? And not done what she had promised by the sound of it. She would pay for this, and the Apprentice need not think he had gotten away with anything either.

Quickly the ghost of Queen Etheldredda crossed the floor to a small roughly made box where Jenna kept all her treasures. The ghost perused the box and then Caused the lid to silently open. Poking a long and bony finger through Jenna's possessions, Etheldredda found what she was looking for and then did something that no ghost should be able to do - she picked up the object, a small silver ball inscribed with the letters I.P. - and placed it in her pocket. Then, with a knowing smile, the ghost of Queen Etheldredda walked through the door and Passed Through the much put-upon Sir Hereward.

The ghost of Queen Cerys gave every appearance of dozing in her fireside chair, so when the ghost of Queen Etheldredda sidled in and headed straight for the potion cupboard, she was most surprised to suddenly find her way barred by a very determined descendant.

"You may not pass," Cerys told Etheldredda coldly.

"Don't be ridiculous, child. I have every right to walk the Queen's Way. And I intend to do so. Stand aside."

"I will not."

"You will!" The angry Etheldredda pushed her way through. Cerys, who gasped - not only from the shock of being Passed Through, but also from the surprisingly solid feeling of Etheldredda - recovered just in time to Cause the potion cupboard door to jam shut.

"Two may play at that game," snapped Etheldredda, Causing the door to reopen.

"But only one may win," replied Cerys, Causing the door to close.

"Indeed, child. I am glad you see sense." Etheldredda Caused the door to open.

"I intend to protect my daughter. You shall not stop me," Cerys declared angrily, and Caused the door again to slam shut. Then, before Etheldredda could retaliate, Cerys began to spin. Faster and faster she turned, like a whirlwind, revolving the air in the turret with her until, despite herself, Etheldredda was caught up in the currents and whirled around the small circular room like an autumn leaf caught up in a windy corner.

"Go!" yelled Cerys. With that, Queen Etheldredda was hurled from the room, out of the turret and across the lawns toward the river, where she landed in the middle of one of Billy Pot's careful arrangements of dragon droppings. Angrily, she picked herself out of the mess and haughtily floated toward the riverbank, where the ghostly Royal Barge awaited her.

Head held high and without a backward glance, Queen Etheldredda walked up the gangplank. As she took her place upon the dais, the ghostly barge began to move. Silently it glided away from the Palace gardens and headed for the middle of the river, where it drifted downstream, Passing Through a blockade of boats, which for some reason seemed to be on fire. Queen Etheldredda tutted to herself at the lawlessness of the Castle and comforted herself that it would not be so for much longer. She would see to that.

With a satisfied smile, Queen Etheldredda sat back to enjoy the journey. There was, thought the ghost, more than one way of getting to Keeper's Cottage.

As Queen Etheldredda was being hurled from the turret, Alther was leading Marcia down one of the many flights of back stairs that led to the Long Walk. "What exactly do you mean, Marcia - he wrote you a note nearly five hundred years ago?"

"This morning, Alther ... I opened the Sealed shelf."

"You did what?"

"You know, you showed me once how to do it. There was something there I had to see."

"Not the I, Marcellus?" Alther had become increasingly pale over the previous half hour. Now he went almost translucent.

Marcia nodded.

"You opened the I, Marcellus? But it's been Sealed since before the Tunnels were Frozen."

"I know, I know, but it was a risk I had to take. I saw ... I saw something in Jillie Djinn's calculations for Septimus's Prediction Practical."

"Huh. That woman's always calculating something," said Alther. "I caught her working out the percentage of wear on her new shoes yesterday. Wanted to know exactly how long they were going to last."

"That does not surprise me, Alther. Personally, she drives me nuts. I'm meant to be at the Manuscriptorium now listening to more of her tedious theories. Oh, what a mess."

"Marcia," said Alther, "what exactly did you find in the I, Marcellus?"

"I found..." Marcia started, and then ground to a halt as her voice choked up. "Oh, it was awful."

"What did you find?" asked Alther gently.

"I found a note from Septimus. It was addressed to me."

"Marcia, are you sure?"

"Yes. You know how Septimus always signs his name with that complicated squiggle at the end - I think it's meant to be a number seven?"

"Yes," said Alther. "It's terribly affected, but the young do have the most peculiar signatures nowadays. I just hope he settles on something more down-to-earth when he gets a bit older."

"He can have the weirdest signature he wants, Alther. He can sign his name in strawberry jam standing on his head if he wants to - I really don't mind. But I doubt we'll ever see him get older ... not in this Time anyway."

Alther was silent. He was stunned, for he knew that Marcia was not one to exaggerate. Marcia was silent too, because she had just realized that what she had said was probably true.

"What did the note say?" asked Alther quietly. They had reached the foot of the stairs and stopped in the curtained darkness of the doorway. A brief squall of chill rain battered a skylight high above them, and Marcia shivered as she brought out a scrap of very fragile old paper. Carefully, for the paper was threatening to disintegrate into a pile of dust, Marcia unfolded the note, and squinting in the dim light, she read aloud the words that Septimus had written all those years ago.

Dear Marcia,

I know that one day you will find this note because when I don't come back I know you will look everywhere in the Library and through all the Alchemie things that are there. I've never seen Marcellus's book in the Library but I bet you know where it is. It is probably in that Sealed shelf. I hope you find it soon after I have gone so that you do not worry about me too much and you can tell everyone where I am. I am going to put it in the Almanac section of Marcellus's book. He is writing it for our Time - I mean, your Time. It is not my Time anymore. I will put it in the day that I went so you will know where to look for it. I hope the paper beetles don't eat it.

I want to say thank you as I really liked being your Apprentice and 1 wish I still was, but I am Apprenticed to Marcellus Pye now. You must not worry as it is not so bad, but I miss you all and if you can by any chance come get me (but I don't know how you can), I would be SO happy.

I have to go now, Marcellus is coming.

I came here through a Glass. Jenna will tell you.

Love,

Septimus xxx

"Oh," whispered Alther.