The door to the fume cupboard closed just as Queen Etheldredda's pointy left foot stepped over the threshold of the Great Chamber of Alchemie and Physik. She was closely followed by Marcellus Pye, who did not trust his mother to be alone in the Chamber for even a second. Marcellus looked tired and disheveled after a long night searching the Palace for his Apprentice and the girl his mother insisted was Princess Esmeralda. He was still wearing his formal Master of Alchemie robes that he had put on for the banquet - which were, to his dismay, now liberally splattered with orange sauce. Around his neck, as ever, hung his Keye to the Doors of Time.

Queen Etheldredda marched in, head held high, followed by her Aie-Aie, which clattered behind her, running on its long fingernails. She looked around with her usual expression of disgust. "Forsooth, Marcellus, thou dost a tawdry Chamber keep. So much gold that I hardly know where to rest mine eyes. 'Tis like unto a tinker's bazaar, which is where I trow thou dost buy thy gold trifles and trinkets with which thee doth rattle like a broken cart."

Marcellus Pye looked hurt at his mother's insults.

Queen Etheldredda sniffed disdainfully. "Thou'rt a tender Plant, Marcellus. I shall have my Potion now before thee doth expire from a Fitte of the Vapors."

"No, Mama," came Marcellus's determined voice, "thou shall not have it."

"Indeed, I shall have it, Marcellus. Do I not see it in its glass cabinet a-waiting me?"

"That is not yours, Mama!"

"Methinks thou art a Laggard with the Truth, Marcellus. Thou wert always a deceitful child. Indeed, I shall have it, and I shall have it now." Etheldredda's voice rose to a particularly unpleasant note. The Aie-Aie opened its mouth, showing its sharp, long fang, and screeched in sympathy.

Inside the fume cupboard, Ullr whined - the Aie-Aie's screech made his sensitive ears hurt horribly.

"And thou shalt not mock me," Etheldredda told Marcellus sharply.

"I mock thee not, Mama."

"Thou doth whine like a baby."

"Indeed, Mama, I do not," said Marcellus sulkily.

"Thou dost whine and I will not allow it." Etheldredda's voice reached a new pitch and set the Aie-Aie off again. This time the creature did not stop.

Marcellus put his fingers in his ears and yelled, "For pity's sake, Mama, make that creature cease its screaming 'ere my ears do burst!"

Etheldredda had no intention of making the Aie-Aie stop. It was upsetting Marcellus and that was fine by her. On and on it yowled like a cat caught in a trap. If the noise was painful for Marcellus, it was unbearable for Ullr. He let out a howl of pain and wrenched himself from Snorri's grasp. The next yell from Etheldredda was one of sheer terror as the fume cupboard door burst open and a panther - hackles raised, claws extended, teeth bared - hurtled out.

Unfortunately for Ullr, he found that instead of escaping the noise, he had run straight into the middle of it, for at the sight of the panther, the Aie-Aie ran up Etheldredda's skirts and continued screeching at panther ear level. The big cat's ears felt as though someone was boring into them. Desperate to get away from the noise, he ran across the chamber and disappeared into the Labyrinth.

"Ullr!" yelled Snorri, bursting out of the cupboard in pursuit of her beloved cat. She raced across the room, unhindered by a shocked Marcellus and a terrified Etheldredda, and disappeared into the Labyrinth, hot on the heels of Ullr.

Septimus felt Nicko's muscles tense, and he knew that his brother wanted to chase after Snorri. He grabbed hold of Nicko before he could move. Inside the fume cupboard there was a terrible hush as the door slowly swung fully open, and the three remaining occupants came face-to-face with Marcellus and Etheldredda.

"Forsooth, thou hast some strange creatures in thy cupboard, Marcellus," said Etheldredda somewhat hoarsely after her long screech. "But methinks the Princess Esmeralda has played her little game of hide-and-seek once too often. Fetch the child out, Marcellus. She shall vex thee no more."

"She vexes me not, Mama. And if thee didst but know your daughter as a mother should, thou wouldst know that the child is not Esmeralda." Marcellus glowered at his mother.

"Thou'rt a Fool," retorted Etheldredda. "Who but Esmeralda could she be?"

"She will answer for herself, Mama." Marcellus gave Septimus a wry smile. "I trust they paid thee well for thy services at the Palace?"

Sheepishly, Septimus shook his head.

Marcellus ushered them out, saying, "Come thee away now, for the black snake sleepeth there and thou dost discomfit it. Remember, we shall be taking the venom tomorrow - to add to the Tincture."

"Knave!" cried Etheldredda. "Thou wouldst poison thine own mother!"

"As thou hast poisoned thine own poore daughters, Mama? No, indeed, I wouldst not."

Seeing that she was getting nowhere, Etheldredda changed her tones to a sugary sweetness that fooled no one, least of all Marcellus. "Pray unlock the cabinet, Marcellus, and show me the pretty blue phial, for I do yearn to see at close hand the wonders that my Dearest Son hath wrought."

"Thou hast but one son, Mama," said Marcellus sourly. " 'Twould surely be a strangeness if he were not your dearest son, when placed against an absence of other sons, though I doubt he would remain your dearest of all were you to include your hunting hounds in the reckoning."

"Thou moans and mithers as well as thee ever did, Marcellus. Pray now, show me the phial that I may gaze upon it, for 'tis a pretty thing with much gold upon it."

"Though there may be colloid of gold suspended within, there is no gold upon the phial, Mama," said Marcellus, stung by Etheldredda's sarcastic tone.

Etheldredda lost patience. Like a rat up a drainpipe, she darted across the Chamber and snatched up the phial. "I shall have this Potion, Marcellus, before thee defile it with the venom of the black snake. You shall deny me not."

"No, Mama!" Marcellus yelled, horrified at seeing his precious Tincture about to disappear into Etheldredda's gaping mouth. "It is not ready. Who knoweth what it may do!"

But Etheldredda was not about to break the habit of a life-time and listen to her son. She did not heed the warning in his words. She tipped the sticky contents of the phial into her mouth and choked in disgust, then she doubled up in pain, coughing and retching. The stuff came back up from her stomach and swilled around her mouth, coating her teeth as if with blue tar. Determined, Etheldredda swallowed it again and straightened up, leaning against the bench, pale and weak as a sheet left too long in the bleach by a careless laundress. Unknowing of the effect the Tincture had had on its mistress, the Aie-Aie jumped onto the bench and drained the remaining drops. It licked its lips and ran a long fingernail around the inside of the phial to scrape out the last smears of slime.

Jenna, Septimus, Nicko and Marcellus Pye stared, aghast.

"Thou shouldst not have done that, Mama," Marcellus said quietly.

Etheldredda swayed slightly, took a deep breath and regained her composure, though she still had sticky blue teeth. "I will not be denied, Marcellus," she said as the Tincture began to enter her bloodstream and an exhilarating feeling of power whizzed through her veins. "For I shall rule this Castle forever. It is my right and duty. No other Queen shall take my place."

"Thou must not forget thy daughter, Esmeralda, Mama," muttered Marcellus. "For she must take thy place when the Time Is Right."

Fixing Jenna with a poisonous glare, Etheldredda declared, "Esmeralda shall never have my crown! Never, never, never." With the power of the unfinished Tincture now infusing her whole body, Etheldredda felt invincible. The Chamber began to distort before her eyes, her mealy-mouthed son grew smaller and the tedious Esmeralda became nothing more than unfinished business.

Jenna, transfixed by the sight of her ghastly great-great (and then some)-grandmother's blue teeth and staring eyes, did not react quickly enough when Etheldredda's hand suddenly snaked out and grabbed her arm.

"Let go!" she yelled, twisting away from the vise but succeeding only in hurting her arm even more. The Aie-Aie threw down the phial, leaped onto Etheldredda's skirts and then wrapped its snake-tail around Jenna's neck - once, twice, then three times, until she could barely breathe.

Septimus and Nick rushed to help Jenna but were swatted away by Etheldredda like a couple of irritating flies.

As Etheldredda and the Aie-Aie disappeared into the Labyrinth, dragging Jenna in their wake, Marcellus sank to his knees in despair at the loss of his Tincture, unseeing as Septimus and Nicko picked themselves up and hurtled into the Labyrinth in pursuit of Jenna.

"We'll get her, Nik," shouted Septimus. "She can't have gotten very far. Can't be more than just around the next bend."

But Jenna wasn't. Nicko and Septimus raced through the endless blue haze of the passageways and found only emptiness.