"Are you sure this is the best place to do this?" asked Elsa.

The crystal solarium, bursting with with the scents of earthy, aromatic plants, hardly seemed the best place to exercise her powers. She stood facing Lady Ilia, some fifteen feet apart. Glass hexagons cast rainbows. When Ilia had asked if she wanted to test her powers against hers, this wasn't quite what she'd imagined. "What if I break something?" she called.

"That's why I suggested the solarium. A bit of a challenge spices things up a bit, right?" said Ilia.

"I'll have to take your word for it."

"Besides," said Ilia, "if you broke something, you'd just have to rebuild it for us, wouldn't you?"

A smile grew at the corner of Elsa's mouth. "I suppose I could. Though if I encase you in ice, it's going to hurt."

Ilia's answering smirk. "That's because, Elsa dear, you're working on the assumption you'll be able to hit me."

They weren't alone in the solarium. A small interested crowd had gathered, including several of the princes and a dark skinned tall and silent man she knew only as Khublan. Several members of staff were trying very hard to look like they were doing something.

Ilia was clearly trying to invoke a competitive rise from her. Well, Elsa had a waiting audience. Why not?

So Elsa dumped a pile of snow on Ilia's head.

— Or, the space where she was standing, a second ago.

The snow hit the mosaic floor. Elsa spun round, eyes flashing, to see Ilia stood behind her, covering her hand over her mouth in a mock yawn.

"How did you…?"

"You'll have to try harder than that, dear."

More snow. Elsa whipped round, to see Ilia standing back round the other side, as though she'd never moved. When Elsa attacked again, she found Ilia sat up in a palm tree.

Hands on her hips, she huffed, "Not fair!"

"Fair is relative," sung Ilia.

"You're moving too fast," Elsa said, crystallising the palm tree, before she felt a finger tap her on the back.

Stood right behind her, Ilia smiled. "I'm not moving at all."

"Two sugars, please, honey," Ilia said. Under the speckled sunlight filtering in through the banyan trees, Anna set the tea tray down at the wickerwork table where Ilia sat comfortably. She spilt some of the sugar, unable to keep her gaze from Elsa.

"Umm… is Lady Elsa alright?" she was forced to ask.

Elsa was running around, shouting at trees, and covering everything in snow.

"I'm just teasing her a little," said Ilia with a wink. "A little cream for my tea, too, if you wouldn't mind."

Anna added in a dollop of cream, glancing up to see Elsa dump an avalanche of snow all over the mosaic floor.

"Escape that, if you can—" Elsa cried in triumph, before— "Huh?"

Anna stifled a giggle. Behind her, some of the princes were laughing. Elsa looked at them, bewildered, and turning to Anna raised her hands as though to ask, "What?"

Never in her life had she seen Elsa behave so unashamedly silly before. Anna couldn't look away. How wonderful it was to see her so carefree, so at ease with her powers. Playing with her powers.

This must be how things were when Elsa and I were little, before the accident.

The thought struck her: The accident. If that never happened, Papa would never have closed the gates. And Elsa would never have started being scared of her powers. That's what Khublan removed from her memories.

And yet, that didn't feel a hundred percent accurate. Something else was missing from this Elsa. Something major in her life, without which there would have been no accident, no closing of the gates, no solitude, no fear.

It was, she realised with mounting horror: Me.

It was Anna the sorcerer removed from Elsa's memories.

Without Anna, Elsa might still be laughing and playing with her powers, like this. As though they were something to play with, rather than a curse, a burden like a heavy coating of snow resting upon her shoulders.

She'd been wrong all along in her assumption. That wasn't not-Elsa. This was the Elsa she should have been.

"Go get us another pot of tea, would you darling?" Ilia instructed her. "I think Lady Elsa will need a drink when she's finishing with all that running around."

It was all Anna could do to manage out a trembling, "Y-yes Ma'am."

Once she was out of the solarium, her pace quickened. She needed to be alone. By the time she flung herself into the empty room she'd discovered last night, she could no longer choke back the robs that rose to her throat. She let them go.

It was because of me, she thought. If I was never born, if I wasn't her sister, Elsa would never have… she would have been—

Happy, Anna thought dully.

Since the thaw, she'd always thought she and Elsa needed one another. Now, she realised that maybe, it was her who needed Elsa more.

"Anna, are you alright?"

At the sound of her real name, she started, whirling round to see the strange locked door stood open. And there, in the doorway, stood—

"Elsa!" she gasped. "You— you remember?"

Had the spell been broken?

In a few brisk steps, the space between them dissolved, and Anna clasped Elsa to her.

"I can't believe you're really back," she breathed.

"Anna, I'm sorry, but I'm not your sister."

Pulling away, Anna blinked at Elsa in confusion. Like ripples spreading across still water, the illusion began to falter. Elsa wasn't this tall. She was missing the freckles from across her nose. The longer Anna looked, the less the girl resembled her sister. She joined the last of the dots.

"Ada," she said, stepping away. "I'm sorry. I thought—"

"I understand," said Ada.

Disappointment hit Anna like a punch to the gut. For a moment, she really thought the spell was broken.

But would Elsa really want me to break it?

"What's wrong, Anna?" Ada asked.

"I'm starting to have second thoughts," Anna admitted. "About— getting Elsa's memories back."

"What do you mean?" Ada asked, frowning.

"Elsa seems so happy here… far more so than at home," Anna said. "I guess I never noticed… or made myself not notice— how much pain she was in. I never realised how much her powers were a burden on her, even after she thawed Arendelle."

She must have hated herself for her feelings towards me, Anna thought. That's why she flipped out, and her powers went out of control when I kissed her at the masquerade ball. She'd been hiding it for a long time.

Why didn't she just tell me? Surely she must have known that I could never hate her for anything she did.

But she remembered back to what Elsa said: "If you're disgusted, I'll understand. That would be a reasonable reaction. And if you don't want to see me anymore, that's fine too. I can stay out of your way from now on. That's fine."

The locked doors might have been gone, but only now did Anna realise the distance that remained between them. Even during their slumber parties, lying by side-to-side, close as skin-to-skin, Elsa hadn't been with her.

With a dropping feeling in her stomach, Anna understood how hard those moments must have been on her sister.

Why couldn't Elsa just have talked to her?

"So what are you intending?" Ada asked. "Leave her here in the illusion?

"Well—" Anna swallowed. It sounded bad when you put it like that.

"And what would you do? You're not suggesting you'd stay here, pretending to be a maid, are you?"

Anna pursed her lips. That had been what she was thinking, and Ada must have seen it on her face.

"You're the princess of Arendelle," said Ada. "What about your country?"

It was a perfectly sensible reminder, which was probably why it infuriated Anna so much. She burst out: "What about Elsa? What about her happiness?"

For years, Elsa gave up everything to protect her. She distanced herself from Anna to protect her. And now Elsa was happy, Anna wanted to do what? To drag her back to Arendelle so she could live in fear again? So she could despise herself again?

Because, once Elsa remembered that Anna was her sister, she'd no doubt the affair they were embarking on would be quickly ended. Whatever it was they had for one another…

That would all be over.

"Come with me, Anna. There's something I need you to see," Ada said.

"Huh?"

Ada stood by the strange door, beckoning her with her hand. "Come. There are things you need to understand."

Anna followed her.

Inside was darkness. Dimly, she saw a spiral staircase winding its way down, lit only by a faint glimmer that ran over the rock like water-boatmen skittering over a pond. Hung from a peg on the wall, Ada picked up a jar filled with bright, silver light.

"What is this place?" Anna asked, and her voice echoed. Ada descended down the stairs, and she followed her.

"Magic has seeped into this place," Ada explained.

"Magic?"

"Long ago," Ada said, her boots clicking against the rough hewn stone, "Queen Matilda discovered an ancient magical artifact sunk to the bottom of Speil lake, thought lost for centuries. If the legends are true, it contains untold magical power."

Watching the glimmer dance from stone to stone, entranced, Anna asked, "What does this have to do with Elsa or me?"

"You'll see," said Ada.

The further down they travelled, the hotter it became. Anna rubbed at her sticky neck, wondering how much further they needed to travel.

It seems to go on forever.

By the time the staircase finally bottomed out, the back of her calves were aching. She looked up and found herself in a high-domed chamber. In the centre stood a large, cracked mirror.

It seemed to draw her in.

"Don't get too close," Ada warned her, voice rising sharply.

Anna stopped, looking back at the seeress. "Why?"

"The legends say it was created by wicked sprites to do evil."

And yet, thought Anna, there was nothing foreboding about the Mirror. Despite Ada's warning, she couldn't help but take several steps more forward, to peer into the dark glass.

—To find somebody inside, peering back out. Anna stumbled back in shock.

"My sister!" she gasped. "Elsa's in the mirror!"

Even as she spoke, Elsa smiled, and raised her hand to give her a little wave.

"The Mirror has the same magic as I do," Ada said unhappily. "It'll show you the thing you want the most."

"The thing I want the most?"

"Your heart's desire."

Anna's cheeks pinkened. Elsa was still smiling, hands clasped in front of her skirt. Anna pulled her eyes away from her to look at Ada. She changed the conversation:"So— what does any of this mean?" she asked, loudly.

"Look there. You see how several of the pieces are missing?" Following Ada's gaze, Anna saw how several large slivers of mirror were gone. The Mirror was incomplete. "For years I've helped the Queen collect the missing pieces of the Mirror. But that's not the only thing she needs to complete it. To do so, the Queen needs people with strong magical powers."

"That's why she needs Elsa."

"Yes. The wedding isn't important. The Queen was never interested in Elsa marrying Jareth, she just needed a reason to lure her here. The solstice is coming up, the day when magic is at its strongest. On that day, Queen Matilda will use our magic to complete the Mirror."

"And then what will happen?" asked Anna.

"Honestly… I'm not sure," Ada said, her voice softening. "The Queen says we will achieve eternity. What that means, she hasn't confided in me. Whether it will warp the laws of the universe, or bring back someone from the dead… I've no idea. Maybe it'll do no harm at all… but…"

"You think something bad will happen?"

"I don't want to find out," Ada said, firmly. "I understand how you must feel about the Queen, Anna, but she used to be a wonderful woman. But year after year I've seen her become more and more obsessed by the Mirror. She's become a slave to it. All the texts refer to the Mirror as an evil artifact, and I fear it's poisoned her. I don't want to see what becomes of her, and us, when it's finally complete." She strode to Anna, and squeezed her hands. "That's why you must wake Elsa from her spell, Anna. She's being used in the Mirror's machinations. You have to take her home, before it's too late."