With the possible exception of Madam Pince the librarian, there was not a soul at Hogwarts who knew the library better than Artemis' best friend Rowan Khanna. Artemis was certain that if anyone could find a Cursed Vault in the library, it was Rowan.

She was delighted when she found that Rowan wasn't the only friend who wanted to help her and Tulip search the library. Penny, Tonks, and even Ben Copper all came along to lend a hand.

"This is great," Artemis told them. "We will be able to cover much more ground with so many of us. We'll find the Vault in no time!"

But despite all six of them searching the library, they had no luck finding the Vault or any clues about its whereabouts.

"Maybe it's not in here, after all," Ben sighed. "We must have searched everywhere."

"Well, not everywhere," said Rowan. "We haven't looked in the Restricted Section at all."

"Let's look there now, then!" Tonks said brightly, before getting shushed by Madam Pince. She made a grotesque face at the back of the librarian's head.

"You can't just go into the Restricted Section. You need a signed note from a teacher to let you borrow any of the books in there," Rowan explained. "And they don't like to give them to students below sixth year unless they have a really good reason. I tried to get one from Professor Vector to learn about Dark Numerology, but she wouldn't sign it for me."

"And if Professor Vector won't give you a note, then it's hardly likely I'll be able to get one. No teacher in their right mind is going to sign anything for me after all the rules I've broken in the past three years," Artemis puffed out her cheeks. "Anyone else got any ideas?"

"I could ask Professor Snape?" Penny said. "He is always saying that I should challenge myself to make harder potions than I think myself capable of."

"As much as Snape weirdly seems to genuinely like you, Penny, that's not going to work," said Rowan, shaking her head. "Even after you get the note, Madam Pince goes in and gets the book out for you."

"Then I really don't see what else you could do," Penny's blue eyes suddenly widened. "Unless..."

"Unless?"

"Well, I might possibly have an idea. Or an idea of an idea, anyway. But it would definitely be breaking school rules. And it would be fairly dangerous."

"Sounds right up Artemis's alley," Tonks sniggered.

"What is it, Penny?"

"I can't tell you now," she shook her head. "I have to check a few things first. But if you come with me to Hogsmeade at the weekend, Artemis, I can introduce you to someone who might be able to help. Actually, Rowan, you'd better come, too."

"So mysterious," Tonks rolled her eyes. "Looks like you, me and Tulip will be going to Zonko's without these guys, Ben. Whatever shall we buy to surprise them with when they get back to the castle?"

The next Hogsmeade trip was on Valentine's Day, and despite not having a date, Penny practically skipped the whole way from the castle to the village.

"It's rather exciting, isn't it?" she said to Artemis and Rowan. "I feel like we are going on a wonderful adventure," Rowan and Artemis shared confused glances. "Now, when we get to Hogsmeade we need to go straight to meet my friend. He's agreed to meet us for a drink."

"Is this your friend that's going to help us?"

"Yes. His name is Talbott Winger," Penny told them. "He's in Ravenclaw."

"In our year?"

"Yes, you'll recognise him when you see him. You've probably not actually spoken to him, though. He's very shy."

When they arrived in Hogsmeade, Penny walked straight past The Three Broomsticks and up the hill to the top of the village.

"I thought you said we are going to for a drink?"

"We are," Penny smiled. "But not at The Three Broomsticks, it will be packed, especially with it being Valentine's Day. No, we're meeting him at the Hog's Head. Much less likely anyone will overhear us."

"Why do I have a bad feeling about this?" Rowan muttered to Artemis under her breath.

Inside the Hog's Head, Penny breezed over to the bar, and gave the barman her most radiant smile. He looked completely confused, and Artemis could see why. Dingy, with a suspiciously sticky floor and a distinct whiff of goats, the Hog's Head was not the sort of pub where you would expect to find anyone remotely like Penny Haywood.

"Good morning! Lovely day, isn't it?" she said, either ignoring or not noticing the puzzled look the barman was giving her. "Please may we have four Butterbeers?"

The barman, still eyeing Penny with a look of mild perturbation, plonked four grubby looking glasses of various sizes on the bar and poured Butterbeer into them. Artemis couldn't help but think that he looked strangely familiar, somehow, even though she had never seen the man before in her life.

"Thank you, sir," Penny beamed at him, as she took out a coin purse embroidered with daisies, counted out eight silver Sickles, and placed them on the wooden counter. "That really is ever so kind of you."

The three girls took seats in the back corner of the room, with Rowan wiping down her seat and a space in front of it on the table before she sat down. She didn't drink from her glass.

"Oh, look. Here he is," Penny stood up and waved as a newcomer entered the inn. "Talbott! We're over here. I've got you a drink."

Artemis recognised Talbott Winger from her Transfiguration lessons, but realised she had never paid much attention to him before. He was of slightly above average height, and very finely built, with a pointed face, long nose, and watchful brown eyes. His hair and skin were different shades of the same tawny brown, and he seemed to glide rather than walk across the room, he treaded so lightly and silently.

"Talbott, thank you so much for meeting me here. These are two of my very best friends, Rowan Khanna and Artemis Hexley," Talbott said nothing, but bobbed his head gently at Rowan and Artemis. Penny smiled and carried on. "Talbott, I invited you here to meet us today because I was wondering if you might be able to help us. As you know, Artemis has been trying to find her missing brother since we came to Hogwarts, and I thought you might be a good person to ask."

"Why me?" Talbott asked, his voice soft and sharp all at once.

"Well, you... have certain skills that might be useful when it comes to finding clues, and getting into places unnoticed," Penny said, cryptically. Artemis frowned at Rowan, who looked as perplexed as she felt. "And, well, everyone knows Artemis is great at Transfiguration, Rowan can find out anything about anything, and I'm not too bad at Potions, if I do say so myself. And then there's you, with all the experience. I thought between us all we could..."

She tailed off at this point and gave Talbott a knowing look that meant nothing to Artemis. Talbott flicked his brown eyes from Penny to Artemis and back again.

"You can't be serious," he muttered.

"Actually, I'm being very serious. As serious as Professor Snape in one of his most serious moods."

"This isn't a game, Penny. This is very complex magic."

"I know that," Penny nodded. She hadn't stopped smiling. "But if anyone can do it, it's us. It's Artemis."

"Do what, exactly?" Rowan asked. "What is going on?"

Penny looked at Talbott as if she were asking permission for something. Talbott inhaled and slowly bowed his head.

"Well, you see," Penny leaned forward and lowered her voice to a soft whisper. "Talbott is an Animagus."

All four of them were silent for few moments. Artemis hardly dared breathe. She remembered suddenly that in Professor McGonagall's lesson, Talbott had been the only student other than Penny who hadn't been totally in awe of McGonagall's demonstration. A million questions danced around in her head, giving her the same strange spinning sensation she got looking at the numbers in Arithmancy.

"Wait, so your idea is for us to work out how to become Animagi?" she whispered.

"Not all of us, just you," Penny replied. "Although Rowan and I could try it, too, if it goes well for you."

"So, you want Artemis to be some kind of guinea pig?" Rowan asked. She looked incredulous.

"No, not necessarily. You don't get to choose what kind of animal you-"

"That's not what I meant, Penny," Rowan hissed. "This is really difficult and dangerous magic you're talking about. I've read all about it in the book Tonks got me for Christmas. If it goes wrong, it can be catastrophic."

"Which is why we will make sure it doesn't go wrong," Penny's smile had finally faded. "I don't want any of us to get hurt any more than you do. That's why I asked you here, Talbott, because you've gone through it before. I thought you could maybe teach Artemis how to do it."

"It was a few years ago. My mother did it with me. She made the potion. I had to cast the spell, and do everything else. If you two can figure out how to brew the Animagus potion, I can teach Artemis the rest," his gaze rested on Artemis. "That is, if you want to do it, Artemis. I know you're good at Transfiguration, but this is a lot harder than anything you'll ever do in class, even with all the extra lessons McGonagall gave you last year."

"I want to do it," Artemis said. "I know it's risky, but it's got to be worth the risk, right?"

Rowan had gone straight to Tomes and Scrolls to look for more books about Animagi.

"I want you both to know that I don't think this is a good idea," she told Artemis and Penny, reproachfully, "but I know Artemis will do it with or without my help. I'd rather make sure she does it properly."

"Oh dear," Penny sighed as Rowan walked away, her head held high, "I do hope she's not angry with me."

"She's not angry, just worried that something will go wrong," Artemis reassured her. "Personally, I think it's a brilliant idea. I've wanted to be an Animagus ever since Professor McGonagall turned into a cat in front of us."

This seemed to cheer Penny up, and as they walked arm in arm, discussing what animals they would want to be, they bumped into Bill Weasley.

"Isn't that sweet?" he nodded at their linked arms. "Happy Valentine's Day to you two."

"Very funny," Artemis pulled a face. "I see you're here by yourself."

"Yeah, about that," Bill grimaced. "I spoke to Emily for once. Turns out you and Charlie  were right about her. She really is fairly unpleasant."

"Well, Bill, I hate to say I told you so..."

"But you told me so, I know," he shook his head. "Thank you for telling me. I'm sorry I didn't listen to you."

"That's alright. Maybe next time you should let me and Charlie pick a girl for you. Make sure she's good enough."

"Maybe just you," Bill laughed. "Let's be honest, Charlie will only think a girl is good enough if she's willing and able to take on a dragon single-handed, and that's really going to limit my options."

"What was that all about?" Penny asked, after Bill left to meet some of the other prefects at the Three Broomsticks.

"Oh," Artemis grinned. "I was just helping Bill with his love life."

"Really? But I thought you fancied Bill."

"What? No," Artemis shook her head. "Why does everyone think that?"

"Well, I suppose it's because you spend a lot of time together, and you always like to talk to him."

"I spend less time with Bill than I do with you and Rowan and Tonks."

"Yes, but that's different, because Bill's a boy, and a very good-looking boy, as well."

"Yeah, he's good-looking, but I don't..." Artemis' voice tailed off, and she frowned. "He's just Bill."

"So, you've never had even the tiniest little crush on him?" Penny asked, with a knowing smile.

"No! Well, not really. Stop looking at me like that," Artemis nudged Penny with the point of her elbow. "I guess when I first met him, I sort of, I don't know... it was just that he was this cool, older boy, and I wanted to impress him. If that makes sense."

"Yes, that makes perfect sense."

"And obviously, I was flattered that he was interested in hanging out with me, but that's all it was," said Artemis, and Penny nodded her head understandingly. "We are just friends, that's all. To be honest, I think he sort of thinks of me like his younger sister."

"So do you think of him like your older brother, then?" Penny asked, before immediately clapping both her hands to her mouth, her eyes wide and remorseful. "I'm so sorry, Artemis. That was really insensitive of me, I just didn't think."

"It's alright, Penny," Artemis smiled at her. "I mean, it's... maybe. Yes," she sighed. "It's hard to explain, but sometimes he'll say something or do something, and it's like I've got my brother back. Or a brother, anyway. Not my actual brother, obviously. It's just... it makes me feel guilty, like I'm betraying Jacob, somehow."

"You can't help how you feel, Artemis," said Penny, squeezing her arm, gently.

"No, I know that," Artemis replied. "I just don't want it to be like I'm replacing him, that's all."

"There's no way you could ever replace your brother, Artemis. Everyone knows how much you love him," Penny said, in a reassuring voice. "Hopefully my plan will help you find him. We just need to make sure we learn everything there is to know about becoming an Animagus before we start actually doing the magic."

It turned out there was a great deal to know about becoming an Animagus. Rowan spent the next three weeks poring over every book about Animagi she could find, before finally presenting her findings to the other girls in the dormitory.

"Let me get this straight," Artemis said after Rowan had told them everything she had discovered, whilst looking over one of the multiple scrolls of notes that she had made. "I keep a mandrake leaf in my mouth for a month, then spit it out into a crystal phial at the full moon-"

"The next visible full moon," Rowan corrected her. "If it's cloudy it won't be any good."

"Right. And then also in the phial I put one of my hairs, a Hawkshead moth chrysalis, and some dew."

"Not just any dew," Rowan said. "The dew has to not have been touched by sunlight or human feet for seven days before the full moon. You also have to measure it with a silver teaspoon."

"So that's the basic potion," Penny said over one of the scrolls. "Well, it's not that basic, it's actually quite complicated, but I think I can definitely manage it for you."

"Thanks, Penny," Artemis smiled. "So the potion matures in a dark place where it is left undisturbed until the next electrical storm. And up until then I have to chant some incantation every day at sunset and sunrise."

"And then when the electrical storm comes, you go out in it, cast the incantation one last time and drink the potion."

"Crikey," Tonks looked appalled. "What a faff. If becoming a Metamorphmagus was anywhere near this hard, I probably wouldn't have bothered."

"Don't you have to be born a Metamorphmagus?"

"Exactly, I didn't have to do a single thing. It's bloody brilliant."

With the help of Rowan and an Astrology chart, Artemis had worked out that the first night back after the Easter holidays would be a full moon. That would give her a full month with the mandrake leaf before she started making the potion. Penny had agreed to gather the other potion ingredients at her next Potions Club meeting, but Artemis would have to collect her own mandrake leaf when they next had Herbology.

"Just a thought, Artemis," Tonks whispered as Artemis stripped a smallish leaf from a mandrake plant and hid it in her pocket. "Have you thought about how you are going to get away with no one noticing that you've got a bloody great leaf in your mouth for a month?"

"Easy," Artemis said. "I'll go to Madam Pomfrey and say I was practising the silencing charm and it backfired."

"Right. And exactly how are you going to tell her this if you've been hit with a bad silencing charm? Through the medium of interpretive dance?"

Tonks screwed up her face, changing her features so that she looked just like Artemis, and started to mime being hit by a spell, and being unable to talk. Artemis laughed and rolled her eyes as she watched herself knock over a watering can.

"Something like that," she grinned. "That should buy me to the end of term. Then I'll just have to go home and not speak to mum all through the holidays, which will be fine. She probably won't even notice the difference."

"Mine would probably die of shock," Tonks laughed, her face Tonks-like once more. "Although she might prefer it. I'll come to the Hospital Wing with you, if you like. It might be easier for me to tell her that you were practising silencing charms and your wand backfired than for you to mime it for her."

Madam Pomfrey was sceptical of Tonk's story.

"Have you been duelling again, Miss Hexley?" Artemis shook her head in response to the Matron's question. Madam Pomfrey fixed her with a withering look and made a noise of disbelief. "We shall see about that. Open your mouth, girl."

After checking that Artemis' tongue was neither tied in a knot nor stuck to the roof of her mouth ("some of these curses students use on each other!"), Madam Pomfrey was satisfied that no duelling had taken place. She wrote a note for Artemis to show to her teachers so that they would not expect her to answer questions in class.

"Maybe I should have pretended to not be able to speak, too," Tonks suggested as they walked back to the common room. "Would get me out of making up predictions in Divination."

"As if you'd be able to go from now until the end of term without talking," Artemis murmured. She raised her eyebrows and pulled out the mandrake leaf. "Well, here goes."

"Any last words?" Tonks grinned as Artemis placed the mandrake leaf into her mouth. "How does it taste?"

Artemis, unable to explain to Tonks the sour, earthy taste of the limp, papery leaf, pulled a face that she hoped told it all for her.

Rowan, as protective as ever of her best friend, had continued her research on the Animagus spell. It had not reassured her in the slightest.

"I just don't think you've taken account of all the risks," she said to Artemis as they waited for their last Care of Magical Creatures class of the spring term to begin. She had been telling her all about the most horrific misfigurations she had found by wizards and witches who botched the process all the way from the castle to the outdoor classroom. "And how do you know we can even trust this Talbott? You know you have to register as an Animagus, right? Well, I checked the register, and he isn't on it! What if he's lying?"

Unable to argue, having a mandrake leaf under her tongue, Artemis took Rowan's hand and gave it a tight squeeze.

"Do you two want to get a room?" a scathing voice said from behind them. Artemis turned around to face Merula Snyde and glowered silently at her. "What's the matter, Hexley? Cat got your tongue?"

"Artemis was hit with a backfiring silencing charm, if you must know," said Rowan, making a tutting noise with the tip of he tongue.

"Well, at least you'll be marginally less irritating now," Merula sneered. "And Madam Pince will be less likely to throw you out of the library next time you go in there sneaking around. I guess you think that's where your next precious Vault is."

Artemis pursed her lips and gave Merula a hard stare.

"Fine, you keep your secrets, Hexley," Merula turned back to Ismelda and Barnaby as Professor Kettleburn approached the students. "Just like your darling brother kept all his secrets from you. It's such a shame that you'll never find him. I'll make sure of that."

Artemis exhaled through her nose like an angry horse, and handed Madam Pomfrey's letter to Professor Kettleburn.

"Dodgy silencing charm, eh?" he chuckled. "The things we do for our magic. Lucky for you we are looking at Bowtruckles today, and they like the quiet. Very well, Miss Hexley, take a seat."

Artemis took a seat at a workbench littered with various twigs and leaves, and was joined by Rowan, Ben Copper, and Charlie Weasley. The four of them worked at carefully removing Bowtruckle eggs from the woody debris to rehouse them.

"I don't like this. It's unnerving, you not speaking at all," Ben said, his eyebrows furrowed together. "And I can't believe one of your charms backfired. You're the best at casting spells in our whole year. If it can happen to you, what hope is there for the rest of us?"

"You're right, Ben, it is pretty unbelievable," Charlie gave Artemis a small sardonic grin that made him look a little like his brother. "I'm guessing you aren't going to tell us what the real reason is for you not talking?"

Artemis and Rowan exchanged secretive glances, before Artemis raised her eyebrows at the two boys and shook her head.