Artemis had never used Gillyweed before, and she would not soon use it again. Its effects were wholly unpleasant - moments after she had swallowed the slimy tendrils of the plant, she felt a searing pain on either side of her neck. Instinctively, her hands went to the place that hurt, and her fingertips brushed over deep ridges in the skin. Gills.

All of a sudden, she felt as if her lungs had become empty. She tried to gasp, but she could not breathe. Looking around at her companions, they were experiencing the same horrible sensation.

"The water," Tulip gasped. "We need to get into the water."

She dived off the jetty, and Artemis and the others followed suit, plunging themselves headfirst into the ice cold water. The second she was fully submerged, the pressure in Artemis' chest lifted. She could breathe at last. She looked down at her hands and feet, and saw that she not only had the plant given her gills, but also webbed fingers and toes.

The effects of the Gillyweed meant that the group were able to swim more powerfully through the lake to the cave which housed the Cursed Vault, with Artemis, Merula, and Ben leading the way through the murky depths.

Just as they had found a year previously, the closer they got to their destination, the clearer the water became. By the time the cave was visible, towering over the inky depths from the point where it extended from the floor of the lake, there was no sign that any life had been close by in years. Artemis felt a chill all over her body that she suspected had nothing to do with the temperature of the water.

Inside the cave, there was no water at all, and the Gillyweed's effects immediately wore off. Artemis took a deep breath through her mouth, feeling the cold, damp air fill her lungs.

"I don't like this," said Penny, staring at the walls of the cave. "I don't like this at all. It feels..."

"Evil," Tulip finished Penny's sentence for her. Beside her, Barnaby nodded, his eyes wide and frightened.

"These places often do," said Bill. He spoke with the confidence of a seasoned curse-breaker, but Artemis could see the way his jaw had tightened. "Come on. It's high time we broke this curse. Which way do we go?"

Artemis pointed at a hole in the wall of the cave, which lead through to a second, smaller cave. With the others following behind her, she led the cave system until they reached a dead end.

"This is it," she said. "Everyone in?"

She waved her wand, casting the revealing spell Professor McGonagall had taught her in her second year, and the whole cave began to rumble and shake. The ground below trembled, and the rocks that formed the cave walls shifted so that there were seven of them, with no exit in sight. In the centre of the Vault, a glowing column rose from the ground. Bill's eyebrows raised.

"This really is it," he said. "So, what next?"

"I'm not sure," said Artemis, frowning as she stared at the glowing column. "Last time I tried Legilimency, but it didn't work. I had to touch the column - actually touch it - and then it..."

Her voice tailed off as she remembered the way the Vault had fought back; the darkness that had consumed her, the terrible memories she had been forced to relive, the feeling of deep and unending despair. She swallowed hard.

"Everything went dark and we all got stuck in a memory loop," Merula explained for her. "All our worst memories played in our heads."

"Don't forget how horrible it felt," said Ben. "Like you'd never be able to feel anything good again."

"So, the Vault is full of a big Dementor," said Barnaby. Everyone stared at him, and he nodded his head sagely.

"I'm not sure what it was," Artemis told him. "But it only went away when we had our hands holding someone else's."

"And do you have the key?"

Artemis nodded in response to Bill's question, and held out the key. "I don't remember there being a lock on the column, though. And if touch it with the key, won't that make the memory loop start?"

Bill's eyebrows furrowed deeply as he looked from Artemis to the Vault and back.

"Maybe," he said. "Okay, this is what we're going to do. Try Legilimency again first, just in case. If that doesn't work, we will have to risk releasing... whatever it is."

"The big Dementor."

"Sure, Barnaby. If we aren't affected whilst holding hands, we can buddy up until we've worked out a way to break through it."

It was as good an idea as any, so Artemis nodded and stared at the glowing column. She tried once, twice, three times to open it with Legilimency, but nothing worked.

"It's no use," she said eventually. "It's weird, like I can't connect with it. It's just pushing me out."

"Okay. Try the key."

"No." Artemis tilted her head to the side. "It doesn't want the key. I think it wants me to touch it."

"It wants-"

"I know, it sounds stupid, but it does. Maybe there's something we missed last time because we were focussing so much on getting out of those memories, or maybe the keyhole only shows up once the memories start."

Bill looked sceptical. "Are you sure about this?"

"Not really, but we've got to try something, so it might as well be this. Everyone hold someone else's hand."

"Wait," said Penny, looking around at the group.

"What, Penny?"

"Well, you're supposed to be leading a circle, aren't you?" she said. "The rest of the Circle of Khanna aren't here, so maybe we should make an actual circle, just in case."

"Fine. Everyone hold two people's hands," said Artemis, and the remaining members of the Circle of Khanna linking hands to form a physical circle around her and the glowing column. She gritted her teeth. "Here goes..."

Artemis' hand trembled as she raised it and placed it flat against the glowing crystal. A second later, nothing was glowing at all. She had been plunged into total darkness. She shuddered. It felt as if she would never see the light again.

In the distance, she could hear a train whistle, and smell smoke. She was standing on Platform Nine and Three Quarters, and a much younger Jacob was crouched in front of her, his face level with hers as a tear ran down her cheek. He wiped it away before standing up and leaving her, and a hand on her shoulder stopped her from following him.

Another hand linked with her own, and the darkness disappeared. Jacob was gone and the glowing crystal was back, and so were her friends, standing hand-in-hand around it. She looked down at her left hand and saw that Merula had taken it in her right. Artemis gave Merula a grateful smile and stepped back so that she was in line with her and Charlie, using her free hand to wipe the tear from her cheek before placing it into Charlie's palm to complete the circle.

"Now what?" she asked. "Anyone see a keyhole or anything? Or got any other ideas?"

"Maybe there's a clue somewhere?" suggested Tonks. "Inscribed on a wall or on the crystal or something..."

But the walls were bare, and there didn't seem to be anything written on the glowing column.

"You could try Legilimency again."

Artemis did so, with no success. The column remained closed, its soft golden glow the only light inside the Vault.

"Nothing," she said, after yet another failed attempt at getting the Vault to open. "It's still shutting me out."

"I wonder..." murmured Ben, but then he shook his head. "No."

"What, Ben?"

"No. Forget it. You can't try that."

"Right now, I'll try anything."

Ben sighed. "Okay. So, last time we were in that loop, we saw things. Memories, visions. I saw what really happened to me when I got stuck in the ice and lost my memories, right? I saw the truth."

"The Vaults of Truth," said Artemis, her eyes widening. "That's what Merlin said the Cursed Vaults were called when Morgana first created them. Maybe that's it, the answer is in the visions you get from the Vault!"

Penny looked at her nervously. "Are you sure that's a good idea?"

"It's got to be worth a try. After all, didn't the prophecy say that I had to go through the darkness?"

"It also said that you had to be guided by a light..."

"Then I'll light my wand first," Artemis said. Her mind made up, she let go of Charlie's hand and drew her wand. "Lumos!"

"Artemis..."

"They're just visions. They can't hurt me. Besides, if I really struggle, one of you can just grab my hands and pull me back."

She pointed her lit wand at the glowing crystal column and steeled herself. Slowly, she released her grip on Merula's hand, and the world went black again.

Artemis squinted in the darkness, trying to see the lit tip of her wand, but it had disappeared, along with the column and the circle of her friends. She took a step forward, hoping that it was a step in the right direction.

It was a step in some direction, at least, and looking down she could see that it was in the direction of the ancient stone arch from the Department of Mysteries, though its veil had been removed and it was no longer whispering.

"Go on, then," said a man's voice from behind her, and she ran towards it, running as fast as she could without tripping on the stone steps, stopping only as she heard her name being called out from behind her.

She turned around to see who had called, and found that she was no longer in the room with the archway, but in the room with the doors outside, all spinning around her. The dizziness she felt was at least a change from the sensation of overwhelming dread and despair, and she welcomed that change. As her mother's teary face appeared in front of her and Jacob pointed his wand to her temple, she felt more confused than she did filled with dread and horror. Artemis frowned, and held on to that feeling as another vision appeared in the darkness. And another. And another.

The visions were coming thicker and faster, and they were all scenes that she remembered from her life. Memories. The night Jacob left, her mother avoiding eye contact, a Devil's Snare wrapping itself around her and squeezing her until she couldn't breathe, Fergus limp in her arms, a bolt of ice bursting out from the door of the first Cursed Vault and hitting Rowan square in the chest.

Rowan...

The silver frames of Rowan's glasses glistened for a fraction of a second before the scene changed again, as if they had caught a fragment of light that Artemis couldn't see. But though she had not seen the light itself, she had seen its reflection, and that was all she needed.

The light was there, somewhere in these memories. She just had to search each and every one until she found it. After all, they were just memories. She'd seen them before, and she could see them again. Artemis steeled herself, determined to find something - anything - even remotely good in the worst moments of her life.

A Boggart advanced on her, but Tulip was by her side. A spider was advancing on her, but Bill was charging at it with his wand raised in front of him. Barnaby was looking at her with an expression of deep sadness in his eyes. She had broken his heart, and Artemis felt awful for it, but she reasoned that if his heart could be broken, it could be mended, too. Rakepick was casting the Cruciatus Curse on Merula, and she was in so much pain that Artemis could feel it, too. But Merula was strong, and so was Artemis. They could deal with pain, wasn't that what Rosmerta had told her once?

A Dementor glided towards her from the trees, and Artemis raised her wand. She tried desperately to cast a Patronus, but she couldn't. How could she, when everything felt so hopeless, like nothing would ever be good again? It was a miracle that she could produce even the tiniest wisp of white light.

Light...

She had to keep on searching, even though it was getting harder. Rowan was in her arms, her heart no longer beating. She was dead, but she wasn't gone, not really, because Artemis carried her with her everywhere, and she always would. That was something. It was something.

Even when Penny and Tonks were looking at her as if they despised the person she had become, and Charlie had her wand and wouldn't give it back, and she beat against his chest and cried until she had no more tears left to cry, she still had something. She had them.

Her heart began to race as the darkness grew bleaker still. She was in the forest once more, and a wolf was advancing on her, teeth bared and no trace of humanity in its monstrous hungry eyes. But she knew now that the wolf was not a monster at all, because it was Chiara. Chiara was a werewolf and that was the truth.

The truth...

Artemis had to keep going. She had to know the truth. But first she had to tell the truth, even though it scared her. Even though it might mean losing everyone else she cared about, but of course, she knew that it wouldn't. The truth would bring her friends closer together, and now the Circle of Khanna were together, and Bill was teaching them how to cast a Patronus, but Artemis couldn't do it anymore. Her Patronus had left her when Rowan had left her, like everyone left her.

But that wasn't true, was it? Rowan could never leave her, not really, and her friends were still here, somewhere in the darkness, and her Patronus had come back to her in the end, quick and powerful and beautiful and made of pure, brilliant light.

Artemis frowned, and raised her hand. She couldn't feel her wand, but she knew that she was holding it. She closed her eyes, making the darkness hers, and hers alone.

"EXPECTO PATRONUM!"

She hadn't intended to call out the enchantment so loudly. Until she had done so, she wasn't sure that she had intended to cast the spell at all. But she had, and when she opened her eyes, she needed to blink as her eyes adjusted to the light.

In front of her was her Patronus, its silver-white cheetah body almost blindingly bright in comparison to the pitch darkness surrounding it. The cheetah looked her in the eye before turning around and padding away from her.

It wanted her to follow it, she could tell. With her wand still raised in front of her, Artemis followed the cheetah through the darkness, one step at a time, until it stopped beside something tall, glowing, and golden. The central column of the Vault.

Artemis nodded her thanks at her Patronus, and stared at the column, willing it to open, but it did not. She placed her palm against the cool surface of the crystal, but still nothing happened. She sighed, and looked down at her cheetah Patronus, which blinked at her slowly.

"You want a go?" she asked it, and she pointed her wand at the glowing column.

The Patronus stepped closer to the column, so close that Artemis could see the tearstain-like markings on its face reflected in the crystal. It bowed its head lower, and touched the column with its nose. The sides of the column sprang apart, but the darkness did not fade.

Frowning deeply, Artemis peered inside the column. there was nothing inside it but a floating ball of glowing light. She stepped up and inside, and the light surrounded her, bathing her in its warm golden glow. She was supposed to do something, she realised, but she had no idea what.

Then, suddenly, she did.

Go, the light seemed to tell her. Go on.

She looked at the light that coated her entire body. She didn't know where the light wanted her to go, but she knew she had to follow it. And she would.

With a deep breath, Artemis closed her eyes, and Apparated into the light.

***

When she opened her eyes again, she was alone. The Cursed Vault was gone and she was somewhere else entirely, though where, she had no clue. All she knew was that she was standing in some kind of spring, though when she looked at her feet, she found that they were not wet at all.

Frowning, she bent down to touch the spring at her feet, but as her fingertips were almost grazing it, it moved out of her reach, towards a trickling stream that led away from her.

She stood back up straight and looked around herself. She could not tell where she was at all. The space around her seemed out of focus, shifting strangely. In one direction, it looked like she was on a cliff path overlooking the sea, in another an orchard, and in a third, a high-ceilinged room like one of the classrooms at Hogwarts.

The only thing that really seemed to be clear was the spring and its stream, though those were both strange. The water - was it even water? - seemed to disappear and fade away whenever she looked directly at it. In her peripheral vision, she could see it better, but it was of no discernible colour, it made no noise at all, and had no set form. It could have been liquid, or air, or even light. Whatever it was, it was flowing away from the source, and for whatever reason, Artemis found herself walking after it.

She had no idea how long she went on for, following the current of the mysterious flowing substance as it meandered through the strange scenery that she could not quite identify.

It was as if neither time nor space truly existed here - wherever here was - and though perhaps she should have felt scared, she did not. Or, at least, she did not feel only scared. She felt warm and peaceful and safe, in spite of the fact that she was walking towards the unknown. It was a strange sensation, but not unpleasant at all. If anything, she felt alive - truly alive.

Eventually, she came to an abrupt halt, as she reached the edge of a precipice, and the ground in front of her stopped entirely. The stream, however, did not. It continued to flow over the edge and down into what looked like a large basin or pool several feet below.

Artemis didn't think twice. She jumped off from the precipice and down into the pool, expecting a great impact or large splash as she hit either the bottom or the surface, but she got neither. She landed in the pool as gently as if she had stepped into it, and the substance inside was not displaced by her arrival at all.

She looked up to see how far she had descended, but the shower of water-light-air behind her seemed to cascade gently down from a height so great that she could no longer see the top, floating gracefully down like specks of dust glowing in a sunbeam.

There was no way of going back the way she had come, Artemis realised, so she would have to go on. Reluctantly, she stepped out of the pool filled with the mysterious glowing substance, and onto the ground around it. She was in a room, she realised, surrounded by dark stone walls, and with a single door directly opposite the not-quite-a-waterfall. She walked to it, and tried to push it open, but it was locked.

"Alohamora," she said, pointing her wand at the door. Nothing happened. "Bombarda!"

But the door stood steadfast and un-openable. She pursed her lips and looked at it more closely. She recognised it. It looked almost identical to the doors of the rooms in the Department of Mysteries, however, this door had a keyhole. Her eyes widened, and her hand reached for the silver Gillyweed key in her pocket. Slowly, she inserted the key into the lock and turned it slowly until she heard a click.

This time, when she pushed the door, it opened. Artemis stepped through it, and found herself...

In the Department of Mysteries.

No, she thought. That couldn't be right. And yet, it was. She recognised the black tiled walls and floors that reflected the blue-flamed candles that hovered between each of the identical black doors.

Behind her, Artemis heard her own door swing shut, and the click of it locking itself once more. Her heart sank slightly as she realised that she had left the key on the other side. She attempted to open the door once more - the scents of a sea breeze, Firewhiskey, leather, and toasted marshmallows piecing her nostrils as she did so - but it was no use. Even if she still had the key, there was no keyhole on this side of the door. She was locked out.

"Congratulations, Miss Hexley," said a voice behind her, and she turned around to see Professor Dumbledore standing in the doorway directly across the circular hall from her. He bowed his head at her, a small smile playing on his lips. "It is rather fitting, don't you think?"

"What is?" asked Artemis.

"Your search for the Cursed Vaults began with a locked door. Now, it has ended with one as well. It is funny how things can come full circle, don't you think?"

"Professor, what are you doing here?"

"Looking for you," Dumbledore said simply. "I suspected that I might find you here this evening, and - as they often are - my suspicions have proved to be correct."

"You mean, you knew the Vaults would lead me here?"

"I knew that the Vaults would lead you to a great power, the greatest power known to wizardkind. I - like many before me - have asked myself what that great power might be. You have now answered my question. I believe, however, that after all these years, I still have not answered many of yours."

"No, you haven't," Artemis told him. "What is inside that room? Why did the Vaults take me there? Does this mean that the Vaults are properly finished now? Do you-"

Dumbledore raised his hand and Artemis fell silent.

"Not here," he said, holding his arm out to her. Apprehensively, Artemis took it, and a second later, found herself standing one floor up, inside the atrium of the Ministry of Magic, right next to the fountain of magical brethren. "I will respond to all your questions once we are back at the castle, Artemis. However, in order to find some of the answers you seek, you must first look a little deeper..."

His gaze grew pointed as he looked down into the fountain. Artemis looked down into the water, and saw a small brown parcel tied with gold string. It was the parting gift her mother had left her back in the summer, the one she had not wanted, in spite of it apparently being half hers. A part of her still didn't want it, but the meaningfulness of Dumbledore's stare made it clear to her that she should take it.

She reached down into the water and pulled the parcel out, feeling firmness of the item inside before opening it to reveal a tiny vial filled with wispy silver fluid.

"Another prophecy?" she asked, tilting the bottle and watching the way the light hit its contents. Dumbledore shook his head.

"Not quite, Miss Hexley. Prophecies deal with the future, this is grounded in the past," he said. "It contains memories."

"Whose memories?"

"Come, Artemis. It is time that we return to Hogwarts and had another of our little chats. It is time for you to know the truth."