Consciousness came creeping back to Anna like a guilty party, tip-toeing in at three in the morning, with foul breath and blistered heels. Her head throbbed, and her first thought was that she'd drunk too much and ugh, why had she done this to herself again?

Spots of light skipping across the film of her eyes, Anna found herself gazing at a bedroom set upon its side that she'd never seen before.

The keening sound of a door opening scraped across her brain, and a blurry figure wavered into her line of sight, blond hair and fuzzy edges.

Blinking hard, pushing herself up off the bed, Anna swallowed down the dryness in her throat and managed out hoarsely: "Elsa?"

But… that wasn't quite right. Elsa was captured by the Queen's sorcerers, and as the hazy bright edges dimmed she saw that it was Ada approaching her side.

"Funny," she said, slumping down on the bed, her head throbbing in protest. "You look more and more like my sister every time I see you. You're not related to the Arendelle royal family, are you?"

Ada didn't answer her, instead taking a seat on the edge of the bed and offering her a drink of water.

"I brought you some food, too," Ada said, as Anna downed the water in seconds. She set on the bed a plate of leftover sauerkraut and sausages. "I thought you might be hungry."

"Good call," said Anna, before she begun stuffing her face. God, she was hungry. The food demolished, her eyes adjusted, Anna took in her surroundings. It was one of the dozen guest rooms she'd helped clean. She'd been dumped onto the neatly made bed, and as she tried to slide her feet off to the side there was a heavy clank. Her ankle was cuffed, and a heavy chain trailed off the sheets to the wall.

"What were you thinking?" asked Ada. "Ilia told me she found you in the chamber in the basement. You were doing so well to not be discovered before then."

Anna winced. That'd been a stupid move. "I guess," she said, swallowing, "I just wanted to see my sister again." The real Elsa. Not Elsa Austenborg. It hadn't been a conscious decision she'd made; the Mirror had somehow exerted a powerful pull, and she'd been dragged right in.

"I don't know what else we can do now your disguise has been blown," Ada said.

Anna started. "You mean you didn't come here to untie me?"

"I had to ask the Queen if I could speak with you. She would know straight away if I let you escape."

"I thought you wanted to help Elsa and me," Anna said in frustration. The sauerkraut she'd stuffed her face with sat heavily in her stomach now.

Ada looked directly at her. "Tell me, then. What would you do if I let you go? Even if you somehow managed to get to Elsa past the guards, how would you get her out of the palace? You know as well as I do that Elsa can't break Ilia's illusions."

"I—" the one word hung, wavering in the air. "I would do something," Anna said at last. She looked at the girl sat on the end of her bed, and the words left her in a rush: "You could. You could do something. Queen Matilda trusts you. You could—"

"I can't," Ada said.

"But why?" Anna asked, brow furrowing. She didn't understand.

"I can't betray her," Ada said. "A long time ago… she saved my life."

"So you're just going to follow what she says blindly? Even though you know it's wrong?" Anna demanded.

Ada's eyes met hers. "When your sister froze your kingdom and people begun to say she was a witch and a monster, you didn't believe them, did you? You ignored them, and went to get her anyway. You helped her stop the blizzard. Because you never gave up on her."

"You… still think you can change her?" asked Anna.

"It's the Mirror that's done this." Ada spat the words. "She… in my memories, the Queen was a different woman. She was kind. Compassionate. She was like a mother to me. It's the Mirror that's poisoned her. And I— I can't betray her."

For a moment, Anna wondered what she would do if Elsa changed. If she became cold and cruel, and did cruel things. Would she be able to love her, if she became someone else?

"I want to ask you something," she said. "Why do you look like my sister?"

"I've never explained my magic properly to you, have I?" said Ada, and Anna shook her head. "I can see heart's desire. And when people look at me, they see their own."

"I— I thought you saw the future," Anna said, lump rising her in throat.

"That's the cover I use. When I was thirteen, the Queen started taking me on trips abroad, looking for the missing pieces of the Mirror. And… to satiate her greed, she used my power to discover the secrets of our hosts, to blackmail and extort them…" Ada spoke very softly, hands curled tightly in her lap. "I… I knew it was wrong. Always knew it, even if I tried to justify my actions in some way. But who was I to refuse the Queen, the woman who raised me? I kept trying to convince myself of that… until I met Elsa, anyway."

"Wait a minute…" everything slid into place. "I always wondered why Elsa decided so suddenly to marry Jareth. Why she just up and left Arendelle. You— you blackmailed her, didn't you?"

Ada flinched. "The Queen needed her here, in the Spring City. The marriage was just a ruse to get her here, and then Khublan could alter her memories to make her want to stay."

"What did you blackmail her with?" Anna demanded. But, even before Ada could answer, it clicked. She looked at Ada's wide, guilty eyes, and the word slipped from her lips. "…Me. You blackmailed her about me, didn't you?"

Ada nodded. She didn't look at her. "I told her we'd publicly reveal the truth about her feelings for you if she didn't marry one of the Queen's grandsons."

She couldn't believe it. Since they'd arrived in this city of illusions and shadow, Ada had been their only ally.

And now she found out that was all a lie, too?"

"I can't believe this. You act like you want to help us, but you're the reason all of this happened," Anna said, seething. "And, what, now you feel guilty about it? Don't you think it's a little late for remorse?"

"I warned Elsa not to come here," Ada protested weakly. "It told her not to do what the Queen wanted."

"Yeah, after you blackmailed her. If you really wanted to help Elsa, you wouldn't have done it in the first place."

"I couldn't just disobey the Queen…"

"Why not? Does she have a chain around your neck?" Ada wilted further, but Anna didn't let up. Anger coursed through her. "You're doing the same thing now. You won't untie me, so you feel guilty, and do some pointless half-measure like this," Anna jabbed her finger at empty plate of sauerkraut she'd brought her. "Well, you can stop it. I don't want your help anymore. Some help that it is. If you really didn't want the Queen to put that mirror back together, you'd go down there and smash it. You're just a coward. You hide behind other people's faces, but I don't even know who you are. And I'm not sure you know, either. Go! Leave me alone. And take your stinking sauerkraut. Go!"

—"and I'm not sure you know, either"—

Wasn't that, after all, really the problem?

To one a daughter, to another a sister, or to another a lover. No one looked at her and saw her.

Who was she?

Anna was right. She was so brave, coming alone to a strange country and putting herself in danger, all for her sister. Ada was a coward. She might make noises of protest, but outward defiance? She couldn't do it. The Queen, after all, was the only one who had seen Ada. The real Ada.

It was the Mirror which had corrupted her. It was all the Mirror's fault.

"If you really didn't want the Queen to put that mirror back together, you'd go down there and smash it."

Ada's mouth was dry. It was so simple. The Queen would be angry at her, but she would forgive her. Once the Mirror was gone, she'd go back to being herself.

She'd look at her and see her again, and not Cecilia.

She swallowed. She could do this. For once, she'd be brave. Like Anna. Smash the Mirror.

In the underground chamber, the Mirror glowed more brightly than ever. The runes that skipped under the skin of the stone walls buzzed agitatedly like a swarm of mayflies.

But something was different. Four stone slabs surrounded the Mirror, and lying upon them—

A gasp wrenched from her throat, Ada was on her knees beside Ilia. Shaking hands found her wrist and felt for a pulse. Only then did Ada's breathing begin to even. Ilia was only unconscious, her face a picture of the serene. She slept peacefully.

Ada eased herself off her knees and through the eerie gloom saw Angus, Khublan and Elsa lying upon the other slabs, sleeping.

The Queen said she needed their magic to complete the Mirror, so why…?

Picking up the heaviest object she could find, an old brass lamp, Ada stepped into the otherworldly glow of the Mirror.

Her own eyes stared back at her.

More than once, Ada had considered that she was likely the only person who looked into this mirror and saw only herself looking back.

"I can tell what you're intending, Ada," her reflection said. Her heart skipped a beat, and she almost dropped the lamp.

"S-since when can you speak?" she managed out.

"The more you've helped put me back together, the more of my power I've reclaimed. And today, my power is at its height," her reflection said, speaking in her own voice, eyes slipping closed. "I can almost taste completion."

"I fear you won't experience that," Ada said, fingers tightening over the handle of the lamp. "You've done enough damage."

The voice that left her reflection in the Mirror was one she'd never heard leave her mouth: it was low, silky, seductive. "Surely you, too, have something you desire, Ada? I can make that come true."

Ada shook her head. "I don't have anyone I desire." Plenty handsome men and beautiful women looked at her with love and lust in their eyes. But they'd always been looking at someone else. "I've wealth enough. I've no interest in fame."

"And yet, there is something you want. A want so painful your heart feels like it could break." Her reflection's eyes, her eyes bored into her own. And Ada couldn't seem to look away. "You want me," her reflection murmured. "You want people to see me. To see you. The real you. You can't stand it when people look at you, and see someone else. You hate it. You hate you. And you lash out. That's why you couldn't help but mock Queen Elsa. You hate her, because she sees her sister, and not you. You hate the world. You hate everything. As much as you love Queen Matilda, you hate her, too, because she sees her dead daughter instead of you. Because—"

"Stop," Ada gasped out. Her fingers, weakly clasping the lamp handle, were sweating. Her heart was pounding. "H-how? How do you know these things?" How did she know them, when even Ada didn't know them herself?

Her reflection smiled. "Come now. I know you've worked it out by now."

No. Ada closed her eyes, but she could still feel her red heartbeat pulsing behind her eyelids.

The similarities had always unnerved her. The Mirror had the same power she possessed. And that's why—

"Why you were wary of me. Why you resisted the idea of eternity when your companions ate it up like ice cream. Deep down, you knew, and you were afraid," her reflection said, pulling her thought straight out of her head before she had a chance to speak them.

"It's— it's true then?" asked Ada, trembling. "You are… this Mirror is…—"

"Yes. I am you, Ada. You are me. We are the Mirror."

"But… how is something like that—" she could hardly breathe, "—even, even possible?"

"Eons ago, we were split into pieces, an enchantment laid upon us that we would never be able to be put back together. Seventeen years ago, Queen Matilda accidentally triggered this enchantment and we were scattered to all the corners of the Earth. With all our pieces shattered, our reflection was broken. It was born again, inside a child. A baby girl. You, Ada."

The Mirror's reflection, inside her? Her fingers tightened painfully, the metal handle of the lantern biting into her skin, denial rising up in throat. "No— this has to be some kind of trick. This is all— all just absurd."

"Then tell me why only you could sense our shattered fragments," said her reflection. Ada opened her mouth, and closed it. She'd always thought it a part of her magic. For years she and Queen Matilda had travelled looking for them. And she had felt them, something twanging inside her like a tuning fork, strengthening and tightening as they drew closer.

Her eyes fixed upon the heart of the Mirror, where still four large shards were missing. "But I was never able to find them all." Something that had always rankled within her— she'd thought it was because she was letting her queen down.

"Untrue," said her reflection. "You've done well, Ada. All our pieces exist now in this very room."

Ada turned from the Mirror, brow furrowed in confusion. In this very room? How was that even possible?

It hit her. Four missing pieces. Four stone slabs. Four sleepers sleeping.

She felt her knees hit the cold stone before she realised she'd crumpled beside Elsa.

"No," she said.

"Why do you think you were so drawn to her?" asked her reflection.

"I thought— I thought I wanted to help her. I thought…" she didn't know what she had thought. Her mind was a mess. She couldn't think.

Now she was looking for it, Ada could feel it, just as she'd felt all the rest. Something twanged inside of her. Nestled in Queen Elsa's heart, cradled by muscle and bone: one of the final four parts of the Mirror.

Part of her.

Her voice was trembling: "If all the pieces are put back together… will I become more than just a reflection? Will I become complete?"

The her in the Mirror was smiling. "We will," she said.

Slowly, her slick fingers released their hold on the lamp. She straightened, her voice strengthened as she asked, "How?"

"Become one with me," said her reflection. She raised her hands, offering them.

Tentatively, and then with more certainty, Ada reached out to her. A noise of amazement escaped her lips as her fingers parted the surface of the Mirror as though it was made of water. She felt the buzz of magic against her skin. Warmth. Light.

Hands clasped her own. And her reflection took her hands and pulled Ada through the glass and into the Mirror.