The following morning, Artemis went straight to the library after breakfast, finding it already busy with students revising for their exams. Artemis was there for other reasons than schoolwork, however. After her conversation with Merlin's portrait before, there were things she wanted to discuss with Corey Hayden.

"I got it all wrong," she told him as soon as she approached him. "Morgan le Fay wasn't trying to destroy the Vaults at all. She was the one who made the Vaults in the first place!"

She had expected Corey to be shocked by her announcement, or at the very least surprised, but Corey simply nodded his head.

"Yes," he said. "I know."

"You know? What do you mean you know? How did you find that out?"

Corey picked up a book and held it up so that Artemis could read its title: The Secret Life of Morgana.

"It was all in here. Sort of, anyway." He sighed and put the book back down. "Artemis, did Rowan ever tell you how much research she had done into the Vaults? Or when she stopped researching them?"

"No, I... Maybe in fifth year? She was upset about not being a prefect and then there was that time we all had that fight in the library and she got cursed by Rakepick. I stopped asking her to help out with Vaults stuff after all that," Artemis swallowed hard. "Why?"

"Because it doesn't look like she ever stopped."

"What?"

"The book itself is pretty shoddy. Speculative history, you know?" Artemis didn't know, but she nodded her head anyway, and Corey continued, "However, there was all this tucked inside it."

He picked up a small pile of folded sheets of parchment. Artemis frowned.

"What are those?"

"Notes. Rowan's notes. Some of them look like more stuff that's been decoded from your brother's research, some of it looks like it might even be Rakepick's - Godric knows where she found that - but the really interesting thing... Well, you know how I was looking into the original leader of the Ronde? The one who thought she was descended from the creator of the Vaults?"

"Yeah. Fortinbras, right?"

"Right. And you remember how I was trying to trace back her family tree to find the creator of the Vaults, but parts of it were missing?" Artemis nodded, and Corey bit his lip. "Well, the bits I needed were tucked into this book. Fortinbras was right, she was descended from the Vaults' creator - or, at least, it looks like she was. If you go back in the tree far enough, you reach one of her ancestors from the Middle Ages, whose name was Avalon le Fay."

"Avalon..." Artemis frowned. "Badeea said that Avalon was the name of Morgana's greatest secret and legacy. She said it was a place, an island, but... You mean Avalon was a person?"

"Her daughter. Maybe, anyway. I tried to look back from Avalon le Fay, but she has no recorded heritage of her own. Then again, if her existence was meant to be a secret, that would make sense, and the dates in which she lived would definitely make it plausible."

"So that's why Fortinbras thought she was the 'heir' mentioned in the prophecy," said Artemis. "Because she thought she really was descended from Morgana, that it meant an actual heir."

"I think that's what makes my theory more likely to be true, actually," said Corey.

"But Fortinbras had it wrong, remember? She wasn't the heir at all."

"No, but she wasn't completely wrong," said Corey. Artemis tilted her head at him, and and he grimaced slightly. "Okay. So, there was another part of the family tree tucked into the book."

"Right..."

"But this one went forward, and not back."

Artemis' eyebrows furrowed deeply. "What do you mean?"

"So, after Fortinbras was dismissed from Hogwarts, she returned to France, got married, and had children of her own. All of them died childless, except for one, leaving her with one single granddaughter," said Corey, fidgeting slightly in his seat. "Her granddaughter attended Hogwarts, and though it looks like she had nothing to do with the Vaults, she did marry an Englishman." Corey swallowed. "An Englishman by the name of Hexley."

"Hexley," Artemis repeated. "You mean..."

"Your great-grandfather."

Artemis said nothing. She could think of nothing to say, nor was she sure what she thought at all. She felt almost as if she were underwater, like she could be swimming beneath the surface of the Black Lake.

"That's why this Cabal, the Ronde, have been so interested in you and your brother from the beginning," Corey continued, as if he were trying to fill the silence that Artemis had created with her own loss for words. "Because you are descended from their original leader, and if Fortinbras was right - which it looks like she was - the creator of the Cursed Vaults as well. That's why you were able to pick up that prophecy, because when it says about the 'inheritance'... It literally was always yours to inherit."

Artemis nodded and swallowed hard, still unable to think of anything to say. When she finally did manage to find her voice, it was quieter than she had anticipated, and hoarser too. "And Rowan... She knew all of this?"

"It looks that way, yes."

"But... But why didn't she say anything?"

"I, um... Well, I don't think she had the time," said Corey. He picked up the smallest scrap of folded parchment and passed it to Artemis. She looked from the parchment to him and back, frowning. "This was in the book, too. I think she left it in the Hospital Wing the day she died."

"Why do you think that?"

"I think you should maybe read it."

Slowly, Artemis unfolded the parchment, revealing a handwritten note. The handwriting was familiar, but less neat and more spidery than she remembered, as if Rowan had written the note in a rush.

The prophecy says that the Vaults need a sacrifice to be opened, and Rakepick knows that. She thinks Artemis is the life that's needed, but she doesn't need to be. Rakepick won't ever see that, and we all know that there is nothing that woman will not do. Artemis is going to the forest tonight, and I think it might be a trap. She has to be stopped, before it's too late.

Artemis scanned the note again and sighed. "That's why Rowan went to the forest that night. She learned about the prophecy and Rakepick, and she was coming to warn me."

"I think so, but don't you think that the-"

"I'm sorry," said Artemis, folding the parchment over. She didn't want to look at that black inked writing anymore. "Sorry, I just need to... I'm going to go."

Not sure why she suddenly felt so uneasy, Artemis placed the parchment back on the table, and stood up from the table.

The library was blurry, and her mind buzzing with unanswered questions. How had Rowan managed to piece together this puzzle, and why hadn't she told her before that night in the forest? Had she known how much danger she was putting herself in when she decided to follow Artemis that night? Had she been scared?

But there was no way to know. Only Rowan could ever know, and she was gone. There was no way of asking her now, not unless Artemis could find a way of going back in time, or find a way of talking to the dead...

Artemis blinked. But of course, she could talk to the dead. She had talked to plenty of dead people in her life. She shook her head, cursing herself for her own stupidity. Why had she never considered it before?

"Where are you going?" Corey called after her as she turned and walked away from him.

"I just need to go to the bathroom."

***

The morning light streamed through the stained glass windows of the prefects' bathroom, with tiny spots of colour appearing on the floor as the mermaid in the window flicked her tail and combed her hair.

"Duncan?" Artemis called into the room. "Duncan, are you there?"

"Really?" said a voice from behind a sink, and a second later, Duncan Ashe floated through it with a scowl on his face. "Will you ever let me just rest in peace?"

"Sorry, I just wanted to ask you something."

"About the Cursed Vaults, of course. I should have known."

"Actually, no." Artemis shook her head. "It's about being a ghost."

"What about being a ghost?"

"How did you get to be one?"

"Ah, well," Duncan raised his transparent eyebrows, "first your brother betrayed me to a criminal organisation, and then I was murdered, and now here I am."

He pulled a face at Artemis, who was not in the mood to pull one back at him.

"No, I mean... Does everyone become a ghost when they die, or just some people?"

"Obviously not everyone. Otherwise the world would be overrun with ghosts, wouldn't it?"

"I guess," Artemis shrugged. "But why some and not others?"

Duncan frowned. "This is about your friend, isn't it? The one that died?" Artemis nodded her head, and his face softened. "Well, I don't know exactly, but for me, I think it was because I was scared."

"Of dying?"

"A bit, but more just of moving on generally. I always was, really. Like I wanted to be a curse-breaker, but more than that, I was scared of leaving school to do it properly, which is why I wanted to break the curses on the Cursed Vaults. And then, when I died, I was so scared of being forgotten about and missing out on things that I felt really bitter about it. Dying. I still do feel that way."

"I'd never have guessed," muttered Artemis. "Look, I know you think Jacob betrayed you, but-"

"I don't think, Artemis, I know," said Duncan. "You can think what you like, but there's nothing your brother wouldn't do if he felt he had to. Nothing." Artemis pursed her lips, and he shook his head sadly. "That's why I've always given you such a hard time. Because I can't get over how Jacob could have stopped at nothing to save me, but instead he chose you, because he cared about you more. I know it's pathetic, and I should move on, but it hurts. I think it would've hurt a bit even if it hadn't meant that I ended up like this."

"What about dying? Did that hurt?" Artemis asked, before she could stop herself.

Duncan shook his head. "Only my pride. That's probably why I'm still here. Too proud and stubborn and scared to move on, so I'm just clinging onto the tiny little bit of life I have left. Pathetic, really."

"It's not pathetic," Artemis told him, shaking her head. "I'm a bit scared to move on, too. From here, and from Rowan, and from the  Vaults too, I guess. I hate them, I really do, but they've been such a part of me, that once they're gone... Well, I'm not sure what I'll do."

"You don't have to worry about that," said Duncan. "The Vaults will never be gone."

"They will, I'm going to make sure of it. I'm going to destroy them, once and for all."

"You can't. It's impossible."

"I can and it's not. My friends have been helping me, we've opened all of them except for the last one."

"And do you know how to open the last one?"

"Well, no," Artemis admitted. She frowned. "Do you know how, Duncan?"

"Nobody knows how, because it's impossible," said Duncan. "Although..."

"Although?"

"Well, Olivia said something about a key once."

"A key?" Artemis wrinkled her nose. "What kind of a key?"

"Just a regular key. She said it had to be to open the final Vault, but Jacob and I were concentrating on opening the Forest Vault then, so we weren't paying that much attention to anything to do with the last one."

"Why did she think it was intended to open the final Vault?"

"It was decorated with some kind of water plant. Gillyweed, I think."

Artemis' eyes widened. "Hang on. I think I know the key you mean! Rakepick had it, she found it in Filch's office. She tricked me into going in there so she could get it." She bit her lip before sighing, "But if Rakepick had the key, she probably gave it to the Cabal."

"Or to Jacob, maybe."

"No, Jacob never mentioned the key when we went to the Sunken Vault. He'd have known about it, surely."

"Then it'll be with the Cabal," said Duncan, matter-of-factly. "I don't think there's any other person Rakepick would ever trust with something that valuable."

At the word valuable, a thought struck Artemis.

"Not another person, maybe," she said. "But I can think of someone who might have the key. I'll have to write to my great-uncle."

"Why would Rakepick give the key to your great-uncle?"

"She wouldn't. But he's taken on her old Niffler, and if Rakepick's most valuable possessions were going to end up anywhere, it would be with Sickleworth."

"It's got to be worth a try," Duncan said. He looked contemplative for a moment. "Artemis?"

"Yes, Duncan?"

"If you manage it, destroying the Vaults, I mean... Will you tell me?"

Artemis nodded. "Yeah, of course I will."

"You promise?"

"I promise."

***

When Artemis left the prefects' bathroom, she did not go straight down to the owlery to send a letter to her uncle. Instead, she ascended the first set of stairs she came to, with one thing on her mind.

The previous year, she had found a magical mirror in the Room of Requirement, one which had given her a way to see Rowan. The mirror had ultimately done her more harm than good, and she had promised Charlie that she would never go back to it. Promises between friends were important, and she had never had any intention of breaking that promise, but given the discovery of Rowan's extensive research, and the fact that she was so close to destroying the Cursed Vaults for good, she felt the need to see Rowan one last time, to thank her properly so they could both move on. Charlie would understand that, and she was certain that he wouldn't mind her making a small exception, just this once.

Nevertheless, she felt her guilty conscience increasingly niggle her as she climbed the steps to the seventh floor of the castle. By the time she reached the Room of Requirement, she was almost relieved to see that the door was already visible in the wall. Someone else was using the room, which meant that her plan had been scuppered. Who the other person was and what they were doing was a mystery, however.

She pushed the door open slowly, revealing the cluttered high shelves and stacks of artefacts of the Room of Lost Things.

"Hello?" she called out as she stepped inside the room. "Who's there?"

There was a shuffling sound from behind a bust of an ugly warlock, and a moment later, a sandy-haired head poked out from behind it.

"Artemis," said Ben Copper, his eyes widening slightly. "What are you doing here?"

"I... I dunno. It doesn't matter now. Why are you here?"

"I was looking for something."

"Have you found it?" Artemis asked, and Ben shook his head. "What is it?"

"Nothing. Not actually nothing, but it doesn't matter either."

"If you tell me what it is, I could help you look."

Ben sighed before telling her, "It was a letter."

Artemis smiled, and the two got to work, searching through the masses of artefacts for Ben's lost letter. It was harder than trying to find a bowtruckle in an hedgerow, but eventually she found a single white envelope tucked into an empty portrait frame.

"Is this it?"

She handed the envelope to Ben, who opened it and read the letter inside surreptitiously before nodding.

"Yeah, this is it. Thank you."

"You're welcome," Artemis smiled. "Who is it from?"

"It's from me," said Ben.

"From you? Who are you writing to?"

"No one in particular. Just... I wrote it a while ago." Artemis cocked her head at him and he sighed before telling her, "Before we went to the Cursed Vault in fifth year. I wanted to write it in case I... Well, you know. In case anything happened to me."

"Right," Artemis nodded, but she did not stop frowning. "So why are you looking for it now?"

"Because Penny told me how you all broke the curse from the Buried Vault yesterday, and so I know it won't be long until we go to the final Vault. I thought I might need it, you know?"

"The Vault isn't dangerous, just horrible."

"It's not the Vault I'm worried about, it's the Cabal. What if they figure out what we're planning and try and stop us?" Artemis hadn't considered that, but before she could respond, Ben continued, "At least now I have this ready, just in case."

Ben's cheeks were pale, but he jutted out his chin stubbornly. Artemis' eyes drifted down to the envelope in his hands.

"Can I read it now?" she asked him, but Ben shook his head. "Please? I'd like to know what it says, but I don't want to think that you might die."

"Not thinking about it won't stop it from happening."

"I know that, Ben. We both do."

Ben nodded his head slowly, and sat on the edge of a nearby table. "It just says thank you to my family and friends for being there for me, that's all. And I said how much I admired each of you, and why. Like Tonks for being funny, and Penny and Charlie for being kind, and you for being brave, and Rowan..." He swallowed before adding, "I apologised to Rowan, too."

"What for?"

"For not being able to remember what happened to me in that ice. And now I do remember, and she'll never know, because I'll never be able to tell her."

"No," Artemis said sadly, joining Ben where he sat. "I think that all the time, all the things I'd like to tell her about or say to her, but never will."

"I just wish I could thank her," said Ben. "She saved my life that night in the forest. If she hadn't jumped out in front of me, I'd have been the one Rakepick hit with that curse. I don't even know why she was there, but she was, and she saved me."

Artemis said nothing. She knew now why Rowan had been there in the forest that night; because she had pieced together the parts of the puzzle, because she had known that Artemis was walking straight into a trap, because she had wanted to save her, because she had been the cleverest, bravest, and most loyal person Artemis had ever known. Because she was Rowan.

"Part of me thinks it was a waste," Ben continued. "That I'm wasting it."

"Wasting what?"

"The chance Rowan gave me. That's why I wanted to go to the Sunken Vault last year and to the Ice Vault this year. It's why I fought the Ice Knight so hard, to prove to myself that I was worthy and brave, but..."

As Ben's voice tailed off, Artemis frowned at him. "But..."

"But if anything, it made me feel worse," he explained. "Because Rowan died to give me a chance to live my life, and only a year later, I go charging at the Ice Knight and don't even think twice about how I was throwing away that chance. I mean, I was okay in the end, I've still got the scars" - he pulled up his jumper and showed one to Artemis - "which Madam Pomfrey said won't ever go away, but otherwise, I'm perfectly alright."

"That's a good thing, though."

"It is. But now I can't stop thinking that if I had been killed by the Ice Knight, then I'd have died without getting to do so many things. Things that Rowan would've probably liked to have done, but never got to, because she died saving me. Does that make sense?"

"Sort of," Artemis gnawed on her bottom lip as she considered Ben's words. "So, you want to do all the things Rowan never got to do? Like be a professor and stuff?"

"No, not that exactly, I just... I just don't want Rowan to have died trying to save someone who never actually does anything with their life."

"You do lots of things."

"Hardly," Ben scoffed. "I mean, I haven't ever gone abroad, or played Quidditch, or eaten anything with chilli in, or..." he stopped abruptly. "Never mind."

Artemis looked at him. "Or what, Ben?"

Ben's pale cheeks turned bright pink. "Um, well, I've never even... you know..."

"I don't know."

"Kissed anyone. Not properly, like."

"Oh, right." Also with heat rising in her face, Artemis shuffled away from him a little. "The thing is..."

"That wasn't a hint or anything," said Ben, his cheeks growing redder by the second. "I just meant that if I died right this second, there'd be so many things that I never got a chance to do, and I should have tried harder to do them. Because if I don't, then Rowan would've died to save a big loser, and she deserved better than that."

"You're not a loser, Ben," Artemis told him. "And besides, it wasn't just you she was trying to save." She looked up at the ceiling and swung her legs as she thought of that final, hastily written note Rowan had left tucked into the book about Morgana. "It was me, too. She figured out that it was all a trap, and went to find me. She jumped in front of the curse for you, but she was there for me. She saved both of us that night."

There was a short pause in which neither Ben nor Artemis spoke. In the end, it was Ben who broke the silence.

"I suppose it always was the three of us in the beginning," he said

"Yeah, I guess so."

"I was so happy that you two wanted to be my friends. Rowan was so clever, and you weren't ever scared of anything. I was so scared that first time I asked to come and sit with you in the cloisters. I thought you'd tell me to go away."

"We wouldn't have," Artemis half-laughed. "Remember, I wasn't exactly the most popular person back then, either. Everyone thought I was mad because of my brother and the Cursed Vaults."

"Now you're a hero because of the Cursed Vaults."

"I don't think anyone thinks that."

"I think that."

"You're the only one, then," giggled Artemis. Ben gave her a weak smile in return.

"It's weird, isn't it?" he asked. "It feels like hardly any time at all has passed since then, and it feels like a lifetime ago, too. So much has happened, and everything has changed."

"Not everything. The clock is still the same at Hogsmeade Station."

"What?"

"Nothing, it doesn't matter," Artemis said. She shook her head to clear the strange bittersweet feeling she had at the memory of her and Rowan standing beneath the station clock. "But you're right, lots of things are different."

"Do you think we're different?"

"What do you mean?"

"With everything that's happened, I feel like I'm not even the same person I was back in first year."

"I think you are," Artemis told him. "I know what you mean, though. After Rowan died, I thought I'd never be the same again, but when I got my patronus back, it was still a cheetah. So, at least some things about me are just as I was before. I've just... grown up. We all have."

"Maybe," Ben didn't look convinced. "Even after everything we've been through, I still don't feel like I'm completely grown up just yet."

"No, me neither."

"And we've been through a lot, haven't we?"

"Yeah, I guess we have." Artemis smiled at Ben, and he returned her smile, his sticky-out ears lifting into his sandy hair as the corners of his lips turned upwards. She narrowed her eyes slightly.

"What? What's wrong?"

"Nothing, I just... Okay. Let me get this straight, yeah?"

"I don't-"

"You're my friend, and you've been there since the beginning. The very beginning. If I was going to realise that I fancied you, I think I would have done it by now," said Artemis, matter-of-factly. "I'm not interested in being anything more than your oldest friend, and this is not going to change that. This isn't a happy ending love story, understand? Ben. Do you understand?"

"I understand what you're saying," Ben replied, frowning deeply. "But I don't understand why you're saying it."

Artemis said nothing. She had said enough. Instead, she leant across and pressed her lips to Ben's, rendering him wordless as well.

Around them, the Room of Lost Things was silent, but outside its windows, a swallow was singing the song of a new summer that neither of them could hear.