"Have you ever heard of casing a joint?"

Tulip, Tonks and Artemis were discussing their plan to sneak into the library during Transfiguration class. They spoke in hushed tones, the hoots of the owls they were supposed to be turning into opera glasses masking their conversation.

"Casing what joint?" Artemis asked.

"Basically, one of us goes on a preliminary visit to the library, gets an idea of what's what before we go in for real," Tulip explained. "Obviously, Artemis, that's going to be your job. What with your, well... newly acquired skills."

Artemis nodded. Ever since her birthday, when she had completed the ritual to become an Animagus, she had been practising turning into a cat for fun in the dormitory, much to the disgust of Fergus. So far, she had mainly used her Animagus form to entertain herself by hiding under Tonks' bed and swiping at her ankles when she woke up in the mornings, so it would be a welcome change to use the skill more productively.

"Right," she said, "so I sneak past Pince, take a look around and see if I can find the entrance?"

"Exactly."

"And what do we do in the meantime?" Tonks asked. "Twiddle our thumbs?"

"Well, I intend to have another search of Artemis' brother's room. See if there are any more black quills," said Tulip, stroking her owl's beak with her forefinger. "Tonks, we are going to need a way to keep Madam Pince off our scent whilst we go into the Vault. Reckon you can come up with something?"

"Is Dumbledore really, really old?" Tonks laughed. "Of course I can. Talking of Dumbledore, he hasn't been around the castle in ages, has he?"

"Hagrid said something about him looking for a Curse-Breaker at the beginning of the year," said Artemis. "He probably just hasn't found him yet."

"What does he need a Curse-Breaker for?" Tonks grinned. "He already has us."

Professor McGonagall walked past them, and Artemis quickly transfigured her owl into a pair of ornate opera glasses, earning her a small smile from the Transfiguration Professor.

"She's impressed by that, wait 'til she finds out-"

"Shut up, Tonks," Artemis hissed. "She isn't going to find out unless you go opening your big mouth."

"Alright, alright. There's no need to be catty."

Artemis stole into the library after classes finished for the day. It was rather busy, mainly filled with fifth years revising for their O.W.L.s. Artemis gave a smile of recognition and a wave to Bill, who narrowed his eyes at her in suspicion, before she hid behind a bookcase to transform into her cat form.

Cat-Artemis padded silently through the library in the direction of the Restricted Section. She wound around the bookcases and passed under the tables where the fifth years were revising, brushing against Bill's left ankle as she walked by him. Her Animagus form was an excellent disguise; even Bill didn't recognise her.  

The Restricted Section was separated from the rest of the library by a pair of gated doors. Crouched low to the ground, Artemis watched and waited for Madam Pince to turn her back to her before she sprang up and over the gate, landing on the opposite side, front paws first.

The books in the Restricted Section were larger and dustier than the ones in the main part of the library. Rowan would have a field day in here, Artemis thought to herself as she twitched her whiskers. The majority of the books looked like they hadn't been touched in years, other than one open open tome on a stand in the centre of the Restricted Section.

Artemis padded over to the central stand and jumped onto it to look at the open pages. She immediately wished she hadn't; the diagrams showed witches and wizards with some hideous misfigurations, worse than the ones Rowan had warned her about while she was preparing to become an Animagus. Despite the revulsion she felt, however, she found herself unable to stop looking at the images.

From outside, the bell of the clock tower chimed, distracting her from her morbid fascination. Of course, she remembered, she had come here for a reason. She jumped down from the stand, landing on her front paws again, and continued to meander around the Restricted Section, looking for something that could provide a clue to the whereabouts of the Cursed Vault, but found nothing.

She wished Rowan had come with her. Rowan knew her way around a library better than anyone, and she was the one who, the year before, had noticed that one of the walls in the ice room looked different to the others.

That was it, realised Artemis. The stairs that had led to the Vault of Ice had been hidden behind that enchanted wall. It would make sense for the next Vault to be hidden behind something similar. She could recall countless adventure stories in which a bookcase had provided a secret passageway, after all.

She decided that this would be a good avenue to explore, so she started to work her way around the perimeter, looking carefully at the bookshelves that lined the the walls of the Restricted Section. Surely, something would mark one of them as the entrance to the Vault, perhaps a mark carved into the wood. That was how she, Rowan and Ben had found the secret duelling book in her first year, she remembered, as she reached the corner of the Restricted Section that backed onto the far right hand side of the remainder of the library, where she knew that the shelf holding the duelling book stood.

But there were no marks on the shelves, no different colours to the wood, none of the books looked like they might be cunningly disguised levers. In fact, one of the shelves in the corner didn't even have all the books on it. There was a gap in the row of books where someone must have borrowed one of them. Artemis couldn't help but wonder what the missing book might contain, who could have borrowed it, and what teacher would have signed the note to allow them to do so. Unless...

Artemis pricked her pointed ears, and looked over her furry shoulders to make sure that no one could see her. Returning to her normal body, she pulled her wand from her robes and pointed it at the space on the shelf where a book was missing.

"Revelio," she whispered.

Nothing happened. Disappointed, she returned to her cat form, and padded back out of the Restricted Section into the main hall of the library.

Bill was still hard at work, a text book open in front of him, his quill wiggling as he furiously scribbled down notes. He looked like he could use a break, Artemis thought, so she jumped up onto the table, sauntered up to him, and sat on top of his open book.

"Hestia," said Bill, frowning at cat-Artemis and then at a black-haired girl in Gryffindor robes who was sitting across the desk from him. "Is this your cat?"

"No," said the girl, not looking up from her own revision, "I don't have a cat."

Bill looked at Artemis again. He still didn't recognise her. Artemis smirked to herself, or at least, smirked as much as her feline features would allow.

"Shoo," whispered Bill, waving one of his hands at her. Artemis didn't move. She swished her tail, and miaowed in his face. She could tell that he was getting agitated, which was making her game even more fun. Bill sighed, and looked around him at the other nearby fifth years. "Whose cat is this?" he hissed.

The question was met with shrugs and hushed responses of confusion, and Artemis looked around, pleased with the fact that no one could tell who she was.

A pair of hands wrapped around her ribcage and, before she knew what was happening, she found herself being lifted bodily into the air, and down off the table. She looked up at Bill, her ears flattened back against her head. How dare he pick her up? That just wouldn't do.

With an angry flick of the tip of her tail, she jumped back onto the table, and sat next to where Bill was writing. She put out a single paw, and started to bat at his inkpot, pushing it to the edge of the table, where it teetered slightly before falling to the ground with a loud thunk, spilling ink onto the floor.

"What is going on over there?" Madam Pince, the librarian called out.

Artemis decided that it was time to leave. She turned tail, and darted out of the library, before anyone could try to pick her up again.

Luckily, when it came to finding clues, Tulip had been more fortunate than she had been.

"I found another black quill in your brother's room," said Tulip, waiting for Artemis outside the library. "Can you detransfigure it?"

Artemis nodded her whiskered head, and slipped behind a suit of armour to transform back into a girl again. She cast the detransfiguration spell, and the quill changed at once into a scrap of parchment.

"The book will open the way to the Vault," she read aloud, and sighed deeply. "Brilliant. It's a whole library full of books. How will we know which is the right one?"

"Well, were there any odd looking books in the Restricted Section?" Tulip whispered as the two girls walked back along the corridor.

"Oh, they all looked pretty odd," Artemis said, still thinking about the misfigurations she had seen. "Unless... there was a book in the Cursed Vault last year. Maybe it means that book!"

"It's definitely worth a try, at least. Now we just need to find someway of making sure the library is empty when we go in."

"That's easy. The castle's always empty whenever the Quidditch is on."

"Good idea. The final should draw a big crowd," Tulip nodded. "That's only two weekends away. Let's hope Tonks manages to work out a distraction for Pince by then."

"I'm sure she already has done. Want to take a bet on which Zonko's product she's chosen?"

But it turned out Tonks hadn't chosen a Zonko's product at all. Artemis returned to her dormitory to find Tonks sporting a particularly ugly pair of earmuffs.

"What are they for?"

"You'll see," Tonks grinned. "So, when are we getting into this Vault?"

"Soon. Tulip said we should use the last Quidditch match as cover again."

"What? Miss Quidditch?" Tonks looked horrified.

"Did you want to go into the Cursed Vault or not?" Artemis asked her.

"I do," replied Tonks, "but it's the final, and I really want to watch Hufflepuff play. And it's us against Gryffindor. Charlie won't forgive us if we miss it."

"I'm sure he wouldn't mind, seeing as we'd be supporting the other team," said Artemis, "but I guess it's fine, as long as Tulip and Barnaby don't mind missing their teams play this weekend."

Thankfully, neither Tulip nor Barnaby minded missing Quidditch.

"I did try out for the team," Barnaby told them as they walked to the library once the rest of the school had gone to the Quidditch stands to watch the penultimate match of the year. "Beater. But I didn't get in. I don't think the other players liked me that much."

"It's a waste of time, anyway," Tulip replied, and Tonks gave her an offended look. "I don't understand why anyone would put themselves under all that pressure, just for a game."

"You know what I don't understand?" asked Barnaby.

"Why baby mice don't go to school?" Tonks suggested. Artemis shot her a warning look.

"No," Barnaby looked more confused than ever. "It's why Tonks is bringing a plant pot to the library."

"It's just a little surprise for Pince," Tonks told him. "Besides, it's not the weirdest thing anyone has got with them today. Artemis has brought along a broken wand, for some unknown reason."

"It was my brother's," muttered Artemis. She still held on to the slim hope that Jacob might be waiting for her inside the Cursed Vault.

They reached the library door and Tonks pulled out the ugly earmuffs she'd been wearing in the dormitory earlier in the week.

"Right, I'll go in and sort out Pince. Once I'm done I'll come and get you."

She changed her features to those of Ismelda Murk, and strutted into the library, still clutching her plantpot. A minute or so passed, and Tonks emerged from the library looking like herself again. She removed her earmuffs, and beckoned them to come in.

"Merlin's pants, Tonks," Artemis stepped over the unconscious body of Madam Pince, as Tulip bent down and removed the librarian's keys from her pocket. "What did you do to her?"

"I didn't do anything, it was the mandrake," Tonks sniggered. "Don't worry, she'll be fine. It was only a baby, she'll just be knocked out for an hour or so."

"Remind me to never get on your bad side."

The four of them moved quietly through the library to the gates that formed the entrance to the Restricted Section. Tulip used Pince's keys to unlock the door, and the four of them peered inside through the open gateway.

"Right, there were some books left out in the middle, and a shelf with a book missing on the right hand side, closest to this end," Artemis said, pointing in the general direction. The room looked different now that she was a girl rather than a cat. "Barnaby, would you mind staying here and keeping guard while we look around?"

Barnaby opened his mouth to reply, but before he could speak, a voice came from the darkness behind them.

"You're not looking anywhere, Hexley," Merula Snyde stepped out from behind a bookcase, Ismelda Murk behind her. "I knew you were up to something. And here you are again, getting in my way. I warned you what would happen if you stood between me and that Vault. Death wishes must run in families."

"Leave us alone, Merula," Barnaby piped up, his hand on his wand.

"Or what? You'll duel us?" asked Ismelda, and she and Merula both laughed cruelly. "You know that won't work, idiot," Merula said, "I didn't think you could possibly be any more stupid, but here you are running around with Hexley and her gang of circus freaks."

"Artemis is my friend now, Merula."

"You must be the star of the freak show."

"Don't you listen to her, Barnaby," Artemis placed her left hand on Barnaby's arm, her right hand positioned ready to catch hold of her wand. "You know, Merula, maybe you'd have more people willing to help you if you weren't so bloody vile to them."

"Getting you girlfriend to stick up for you," said Ismelda, joining Merula in taunting Barnaby. "Aren't you the big man, Barnaby?"

"Poor little boy," Merula sneered. "You're not just thick, Lee, you're pathetic. Hiding behind Hexley, I wonder what would your daddy say about that?"

It was as if Barnaby Lee was a rubber band that had been pulled too tight and snapped. Faster than Artemis had ever seen him move, he grabbed his wand from his pocket and began to wield it aggressively at Merula and Ismelda. They retaliated, and concerned that the fight was two against one, Artemis pulled out her own wand.

"You two, go and check the places I told you about," she said to Tonks and Tulip. "I'll help Barnaby with these two."

Tonks and Tulip scuttled off into the Restricted Section, as Artemis and Barnaby duelled Merula and Ismelda at the gate.

"Artemis, go with the others," Barnaby panted between hexes. "I can hold back these two."

"But-"

"That was the plan, wasn't it?" he said. "Go. I can do this."

"I know you can," Artemis hurled one last spell at Merula, and squeezed Barnaby's arm gently as she ran through the gate. "Thank you!"

In the right-hand corner of the Restricted Section, Tonks and Tulip were examining the bookshelf with the missing book that Artemis had noticed when she was in cat form.

"Artemis, we think this is it!"

"That's what I thought, too," she told them, "but I tried the 'revelio' spell, and it didn't reveal any kind of magical illusion."

"That's because the illusion isn't magical," said Tulip, and she attempted to pull a book of the shelf. It was fixed solidly in place. "These are just fake."

"It must be a secret door," whispered Artemis, and she reached into the pocket of her robes, removing the book she had found in the Vault of Ice the year before. She stood on her tiptoes, and placed the book into the gap in the row of fakes. It fit perfectly.

The bookcase made a strange clanking sound, and splint down the centre, the two halves folding away to form and opening.

"Cool!" Tonks' jaw dropped.

Barnaby Lee ran towards them from the gate.

"They've gone," he panted. "But they'll probably be going to find Snape at the Quidditch stadium. They will want us to get in as much trouble as possible."

"We'd better be quick, then," Tulip stepped back from the entrance to the Cursed Vault, and gestured with one hand. "After you, Artemis Hexley."

"Everyone get behind me," Artemis said, pulling out her wand as she stepped through the bookcase. "Lumos!"

Artemis led the other three through the the bookcase and down a corridor that was so dark and low-ceilinged that it looked almost like a tunnel. The only light came from their own lit wands. At the end of the tunnel they found a large wooden door, inscribed with runes.

"Alohamora!"

The sound of a lock clicking echoed down the corridor, and Artemis pushed the door open, revealing a heptagonal shaped chamber, lit only by central column made of glowing crystal. They had reached the Cursed Vault.

Artemis couldn't help but find the second Vault much more frightening than the first. It was much darker, and the light from the central column seemed dimmer, colder. The walls of the Vault were cast in shadow, and an ominous hushed quiet hung in the air.

Artemis stepped forward, and as she did, she realised that she and her friends were not the only ones in the Cursed Vault. The other side of the column, something - or, perhaps, someone - was moving in the gloom.

"Hello," called Artemis, shining her wandlight into the Vault, "who's there?"

The figure moved out of the shadows, and into the dim light of the column, its face illuminated by the glowing crystal. Two hazel eyes stared at Artemis, a shadow cast across them by a mop of dark hair as unruly as her own.

"Jacob?" Artemis whispered, and her heart skipped a beat. She took a step forward towards her brother, who gave her a lopsided smirk.

But as he smiled at her, Jacob's features began to change. The smile became cruel and twisted, and his skin paled. His nose flattened, and the nostrils narrowed to slits. The hazel eyes turned red and snakelike as Jacob's dark hair vanished from his head. Artemis recoiled, her eyes widened in terror.

"It's a Boggart!" Tulip shouted from somewhere behind her. "Banish it!"

But as Artemis readied her wand and took a deep breath, the shadows at the periphery of the Cursed Vault began to stir, and from the darkness there appeared six more figures with serpentine features and glowing red eyes.

The seven Boggarts advanced on Artemis, and she stared in horror at their shifting faces: Boggart Jacob, Boggart You-Know-Who, Boggart Artemis. They all hissed at her, but she could hear nothing but the sound of her own pulse pounding in her ears.

"Artemis, banish them quick!"

She steeled herself as the Boggarts drew ever nearer, glaring at all of them, trying to think of something - of anything - that might make her feel less afraid.

"RIDDIKULUS!"

There was a loud crack, and the seven Boggarts transformed once more. Gone were the terrifying figures, and in their place stood Artemis' own friends. But she had never seen any of her friends like this before.

The first Boggart had turned into Rowan, but this Rowan had a large bushy beard. The second had become Ben, and was riding on a one-wheeled bicycle, while a third Boggart in the shape of Penny was doing a series of backflips across the length of the Vault. There were now two Tonkses and two Tulips standing near Artemis, and one of each of them were dressed as clowns, and a second Barnaby Lee, even more muscled than the one standing behind Artemis, was sporting a large handlebar moustache and holding a large and heavy-looking weight above his head with one hand. Overseeing the other Boggarts was Bill Weasley, dressed in a red tailcoat and long black boots, his red hair pulled into a smart ponytail and a top hat perched on his head.

"Uh, Artemis," said Tonks, the real one, standing beside her with a look of mingled amusement and perturbation. "What the actual-"

"Freaks," said Artemis, starting to smile, her fear vanishing from her. "They're circus freaks!"

"Is it just me," came Barnaby's voice from the doorway, "or are they more frightening now than they were before?" The three girls turned around, and saw that Barnaby was standing well back from the Boggarts, eyeing them cautiously. He looked the expressions on the girls' faces and held up his hands. "What? I really don't like clowns!"

Artemis, Tonks, and Tulip all burst out laughing, and the seven Boggarts disappeared in a cloud of smoke.

Artemis walked over to the central column. There were Runes inscribed into the gold frame. To her relief, she recognised several of the symbols.

"What does it say?"

"Well, this one means a locked room, and this one means fear," Artemis said, running her hands over the runes as she translated them. "So, Vault Of Fear? And here are the symbols for open, sacrifice, and magic."

"Rowan would be so proud of you right now," Tonks grinned. Artemis didn't return the smile.

"I think it says that to open it, I need to sacrifice my magic," she frowned deeply, then gasped. "Wait! The wand!"

She reached into her pocket and pulled out the pieces of her brother's broken wand, and touched them to the column. Just like the previous year, the column opened, revealing the contents inside: a map, and a broken arrow. She stepped in to collect them, and as she did, her vision became blurry, and a voice spoke to her through a haze of dark mist.

"Artemis, it's coming," said the voice.

"Jacob?" Artemis called back. "What's coming?"

"I tried to help," Jacob told her, speaking through the mist. "You have your wand. Use your wand."

"Use my wand for what?"

The fog that covered Artemis' vision began to swirl and turn a deep orange colour, and from the twisting mist another figure formed, another cloak, another pair of red eyes. Another Boggart? she wondered, but before she could give the matter much thought the figure raised its hands in front of it, and bright light emitted from its outstretched palms, blazing through the mist towards Artemis.

"Protego!" Artemis called out, just in time. She started to shout the incantations for as many spells as she could think of. "Bombarda! Diffindo! Expelliarmus!"

Her opponent's wand flew towards her, and she reached up to catch it, but the wand went straight over her head, and she started to fall backwards through the air. As she hit the ground, the fog lifted. Tonks was crouching over her, concern in her grey eyes.

"Artemis, are you okay?"

"I'm fine," said Artemis. She realised that she was lying on the ground, and she propped herself up onto her elbows. "Are you all okay? It didn't get you, did it?"

"What didn't get us?"

"The figure, the one I was duelling," Artemis frowned. "Couldn't you see it through the mist?"

"Artemis, there wasn't any mist, and there was only us in here," Tonks placed the back of her hand gently against Artemis' forehead. "Well, you're not feverish, that's for sure."

"No, I feel fine, I'm fine," Artemis shook her head, and sat upright. There was a cut on her arm that was bleeding. "How did that happen?"

"You went to climb up inside the tower thing, then you went limp and were lifted into the air somehow, and just sort of hovered."

"What?"

"You fell back down to the ground pretty suddenly, it's no surprise you cut yourself," said Tulip. She crouched down by Tonks and pointed her wand at the cut on Artemis' arm. "Episkey," she said, and the cut immediately healed. Both Tonks and Tulip rose to their feet, and Tulip continued, "I think we need to get out of here. This place is dangerous, and if we hang around much longer who knows what might happen."

"For a start, we might get caught by Snape or Pince," said Barnaby. He stepped over to Artemis, placed his hands under her armpits, and lifted her onto her feet as if she weighed no more than a feather. "Let's go."

Artemis nodded, and walked back over to the column. She took the map and the broken arrow, and the four of them walked out of the Vault of Fear like soldiers from a battlefield.