This is (again) written with the Exolvo headcanons in mind, a Harry Potter and Frozen crossover started by ultranos, arendellesfirstwinter and counterpunches on Tumblr. Check out the Exolvo tag, there's a Timeline/Masterpost that should easily help you get started, which I'm linking on my profile too. Lots of good reading and fun ideas.

Good reading.

Desire

Night fell, the sun slowly disappearing behind the hills. The sky remained blue and lavender, slowly turning to midnight, refusing to shine gold brighter than the great man's pyre had. With the funeral over and done with, Harry should really return to the castle... But he didn't want to. Not yet, not while it should still hurt, not while he still felt numb.

Dumbledore had been his greatest protector, yet now he was lost. Who was going to protect him? Who was going to defend the school, to avenge their great leader? His thoughts were a jumble, a mess. Flashes of the events of the past few weeks kept playing through his mind. It was as he started walking along the edge of the lake, alone, that the thought struck him.

Harry hadn't seen Elsa at the funeral.

The thought somehow helped him snap out of his ruminations, his brow creasing in puzzlement. The Slytherin prefect hadn't been sent home early. In fact her sister had been a sobering presence at the funeral. Sat at Ginny's side, the solemnity in Anna's usually hopeful features had really hammered home how Dumbledore's passing had not only affected him, but the whole school. Harry remembered seeing the same solemnity on the red-head's features at the funeral of their parents, the year before. Elsa had been unable to attend that funeral due to her injuries; Harry had felt certain that that fact alone would mean the blonde sixth-year would do her utmost to attend this one.

Remembering the fresh sting of Draco's attempt on the Headmaster's life, of Snape's treachery, Harry felt a cold lump of fear grip his heart. Voldemort had wanted Elsa to defect, to join his side, he had seen it. Had she maybe...?

The dark haired teenager shook his head. No, that couldn't be it. This was the girl who would rather fight the Dark Lord then and there rather than risk him threatening her remaining family. This was the one who'd fought alongside him at the ministry, the Slytherin who tutored their own version of Dumbledore's army, the sister who spent eight years hiding from her sibling in order to protect her... There was no way she would defect.

As he puzzled over this, he let his feet guide him along the lake's edge, his eyes sadly glancing at the white tomb erected upon one of its islands, the temporary pier leading to it already dismantled. He thought for a moment that maybe Elsa had stayed in the castle to watch the proceedings from there, some twisted sense of shame keeping her away. Heavens knew the girl was stubborn enough. He cast his gaze momentarily at the school's towers, but the thought was soon dismissed. Unlike the Gryffindor common room, the Slytherin dungeon had no great view of the grounds. He doubted such a private young woman would watch from one of the more public areas. He sighed, fatigue and doubt fraying his already tried nerves.

It was then as the stars started twinkling in the sky above that he noticed the twinkling upon the slopes nearby. The hill was small, but high enough to give a good view of the lake-shore he'd just walked away from. It was near enough to the lake that even the proceedings on the island would have been visible, and the little group of trees and shrubs atop it made any movement there inconspicuous. A suspicion made its way into his heart as he made to walk up it, and it was soon confirmed.

There she sat. The grass at her feet was thick with icy shards. Snow seemed to sit still in the air around her, flakes sparkling at him with every step he took. The student before him didn't move, didn't acknowledge his presence. Her hands were gripped around her knees, her face turned towards the lake. Harry couldn't tell for sure, now that the sun had set, but her eyes looked puffy and dark. The young man felt as though he was intruding yet he felt strongly that he couldn't and shouldn't leave just yet.

"Can I sit with you?" Harry said before his thoughts could catch up to his tongue. The large rock Elsa was sat on looked frigid, despite it being summer. It even had a large crack in its side that he suspected might have been the result of her ice.

Silently, she dipped her head. It was the only acknowledgement of his presence she offered. The snow and ice did not change, in fact Harry was chilled to notice that the small breeze he'd felt along the water's edge had vanished. The air here was perfectly still. Pulling his thin summer robes tight, he sat, his hands stuffed deep in his pockets in an effort to fight the cold. He stayed there quietly a moment, vaguely recalling that Elsa Arendelle's wandless magic tended to manifest itself in such ways when she was angry or upset.

That certainly went some way to explaining her absence. Harry wondered briefly what the relationship between the blonde and the Headmaster had been like. Clearly the man had been more to her than just a professor.

"The lake..." He nearly missed her whisper, Elsa's voice as quiet as a mouse's. "It's like a mirror."

Casting his gaze back to the waters, he realised that this was true. Now that night proper was here, the black waters were still after the merpeople's dirge and the lake seemed to reflect every single spark of light from the heavens above. The surrounding highlands were a blue and grey edging to the beauty it showed. With a pang he recalled one of his earliest interactions with the deceased wizard. He wondered, yet again, if the man he had looked up to really did only see a pair of socks in that magical mirror or Erised.

Elsa's deep sigh beside him brought him back from his recollection. Turning his focus to her, he saw that she had her gaze turned towards him. Somehow she looked as though she was surfacing from the grief she had been drowning in. Harry responded with a sad smile, at odds with the anger he still felt inside him. RAB's message had left a heavy weight in his heart.

Seeing his smile seemed to cause the young witch some amusement, her own lips quirking into a similarly sad smirk.
"I hate to see so many sad things reflected..."

He instantly knew that she was referring to more than Dumbledore's funeral. She was referring to his death, a year after her parents' death. She was referring to the hollowness they seemed to share, reflected in one another. She was referring to so much more than stars drowning in darkness.

In a desperate attempt to lighten the mood and distract himself from the cold, his already heavy breast unable to revisit dark thoughts, he decided to pick up on her mirror allegory instead.

"Speaking of mirrors..." Harry stalled as he realized the possibly personal nature of what he was away to ask the girl, but he had started so he would finish. If anything it might give him some insight into the aloof snow queen of Slytherin's motivations, though something told him he had a suspicion what the answer might be... "If, hypothetically, you were put before a mirror that shows you your strongest desire, your heart's greatest wish..."

A flash of his family made itself seen in his mind's eye, only his subconscious added in an Albus Dumbledore, alive and well, smiling as he waved a pair of woolly socks at him.

"What would you see?" He found it hard not to choke, but managed, somehow.

The platinum blonde eyed him warily, her ice blue eyes staring past him in thought. She turned her face back to the castle a moment, tilting her head as she considered her reply. It was a long time coming, Harry's feet starting to feel numb as he kicked at the ice underfoot.

When she did answer, it was with something akin to a sob and a chuckle. Elsa gazed down at her hands, which Harry noticed were gloveless, as they had been for large chunks of the past year. Her fingers flexed, gently, palms facing skyward. Her voice was soft as she turned her gaze there too.

"I would see a snowman," a pause, a nod, "yes, a snowman."

Harry had been fully prepared for his unconventional friend to lie or remain quiet. He had felt for certain that a truthful answer would involve her sister, maybe even their parents in some way, yet... He didn't think she was being untruthful. He had no idea what it was she meant by a snowman, but he was confident in the way her eyes glimmered and her body language indicated openness that the answer had been heartfelt. She had never been very good at hiding things from him anyway.

"A snowman, huh?" He returned his gaze to the dark waters below. "That's actually... Pretty cool."

He heard her wince at the pun, but he felt no remorse. Even though he was freezing sitting beside her, he was enjoying the companionship, the no-nonsense or pretence in their interactions. It made a nice change from his fellow Gryffindors, so eager to offer comfort or distractions.

A splash of colour on the waters caught his eye. For a moment he thought he was seeing Fawkes again, the phoenix soaring over the lake's surface, and then the colours changed, subtly, growing longer like a snake. Snapping his eyes back up to the sky, Harry gasped at the beautiful sight before him.

"The northern lights!"
There had been mention of them sometimes happening in this part of the world, though he'd heard it was generally in spring or autumn. To have one occur at the height of summer, especially after such a sad event, Harry wondered if this was the act of some other group that the professor had left a positive impression on.

"Huh..." Elsa was definitely becoming livelier. She seemed to quote someone as the next words she said were "the sky's awake."

Harry gave her a quick glance, finding a smile on her face. It was a smile he shared as they watched the aurora together in silence, for what seemed like minutes. He didn't mind the cold so much anymore. The warm summer breeze from the lake was back, despite nightfall, and the snowflakes had both melted and drifted away. The ice underfoot was evaporating with as much beauty as the light show above was providing, giving Harry the illusion of peace, if only for a little while.

When the blonde beside him spoke next, it was in a quiet, confidential voice. One that asked for no reply, it wanted him only to listen. It was the same tone he had used as a child, talking to imaginary rodents in the cupboard under the stairs.

"He came to see me, last summer..." There was no need to ask who he was. His tomb was glowing beneath the aurora, a lonely slab of white stone on an island too small for such a large legacy. "It must have been the day after my parents' funeral. I remember Anna came to visit, but I'd been too... choked up to let her in. Professor Dumbledore never let a closed door stop him though..."

She took a deep breath, leaning forwards into his peripheral vision.

"He told me he had come to apologise." That got Harry's attention. He had presumed the headmaster would have visited the girl to offer his condolences... An apology seemed to imply that he had wronged her in some way, and Harry knew for certain that Dumbledore had had no part in Agdar and Idun Arendelle's passing.

"I... He had been the one my parents had taken me to when I... When Anna had the accident." Even after all had been revealed, Elsa still seemed to have trouble talking about the event that had torn the sisters apart for so long. Harry couldn't blame her though. Some things one can never put into words. "I hadn't remembered it was him, but I've always recalled what was said. He offered my mother and father some advice..."

"It was this advice that we followed. It was his words that led to my sister's memories being taken away, to me hiding my magic from her, hiding myself."

There was a sting in her voice that scared Harry, but before he could fathom why she went on, clasping her hands together and lifting them to her nose.

"He'd never intended for any of that..." Harry's fingers flexed as he heard the deeply felt regret, one that echoed so fully in his chest. "He hadn't realised how badly we had misinterpreted his words, not until after I had started at Hogwarts, and even then, the realisation only fully hit him after Anna started too."

"Fear will be your enemy..." She quoted, her voice taking on Dumbledore's calm drone. A sad chuckle left her throat as she closed her eyes. "We just assumed he meant that others would fear my powers, and rightly so for they can be ever so dangerous..."

It took a moment for her to continue, her hands shakily floating back down to her lap, head low.
"It was that very same assumption that opened the wrong door. By the time Anna had joined Gryffindor, I was so full of fear... My magic would spill forth at the slightest mistake, as you saw, Harry."

At this, Elsa opened her eyes and looked at him with a warm smile, a sharp contrast to the terrified girl he remembered from fourth year. He nodded.

"So Dumbledore begged for my forgiveness and... I was so stunned. I didn't know what to say."

"And did you? Forgive him?" Harry asked. There was only a little touch of ice left around them now. Elsa's face resumed its usual morose expression, her focus returning to the island before them, a soft tenderness in her gaze.

"I figured that there wasn't anything to forgive, and told him as much. It wasn't his fault Anna was admitted to Saint Mungos. He couldn't have known how badly we'd misconstrued his meaning." Brushing some loose strands of hair from her face, she sighed. "I was so exhausted from both my grief and injury at the time I just didn't have the strength in me to be mad or vindictive. He bowed his head and called me gracious, when I felt anything but... I was bedridden, unable to attend my own parents' sending off and I had just realised the full extent of me and my family's biggest mistake... Heavens, I was still shutting my sister out, for the same reason I didn't attend Dumbledore's funeral with everyone else today: I'm scared."

"Elsa..." Harry put a hand on her shoulder, the way she was clenching her jaw forcing him to reach out. "We live in dark times. It's normal to be scared."

The blonde let out a hollow laugh. Somehow she managed to find an unshed tear to cry, the water running down her cheek, sparkling red and green from the aurora above them.

"I just... Sorry." Shaking her head and rubbing at her eyes, the young witch's shoulders slumped. After taking the time to compose herself anew, she turned to him, looking slightly sheepish. "Thank you Harry."

"Hey, it's no problem." Standing, he stretched his sore limbs, admiring the heavenly lights above them once more, but feeling the urge to get moving. "I needed the space too."

"Hm." She hummed.

Harry began the descent back down to the lakeside path, feeling weary and empty, but definitely less frustrated than he'd been upon leaving the ceremony. He didn't check to see if Elsa was following him. If she wanted to stay out here longer, that was fine by him too.

"Hey Potter!"

Startled by the mischievous tone in her voice, he stopped and glanced back towards her. He frowned slightly as the breeze shifted his fringe away from his scar.
"What?"

For all reply, she hurled something white and fast at him. Out of sheer reflex and bewilderment, he pulled out his wand, the spell pouring forth from his lips in a matter of instants. The projectile was deflected and instantly sent back to its creator.

The snowball collided with Elsa's face with an audible thwack. Her hair was now white from more than just its natural colour, and the surprise on her face was priceless. If Harry hadn't been so startled he would have laughed.

"Hey, what was that for?" He asked, confusion keeping his wand raised in a defensive stance.

Wiping the cold clumps from her face, Elsa smirked, clearly bemused that her surprise attack had been deflected so efficiently.

"I remembered something else that Dumbledore told me that day..." She began to swirl her hands around each other, a small ball of white light forming between them. "About something he wished for..."

She arched her brow at him. Harry noticed that Elsa's smirk had turned into a big lop-sided grin, the sort she only seemed to show when truly happy, usually with Anna. He watched, amazed as the ball of light in her hands got flung up into the air, only to turn into a brilliant flurry. The plumes of Elsa's magic arched high into the sky, a display to match the lights above. It wasn't long before the two were surrounded by mounds of soft snow, without any of the ill effects of ice or cold.

"Huh?" Eyes wide at the spectacle before him and the oddness of snow in July, Harry couldn't even manage a proper question.

"Do you want to play?" Summoning a fresh snowball into her hand, Elsa eyed him expectantly. There was no misunderstanding her intentions now.

It took Harry a short moment to process what could have caused the normally well-mannered and solitary student to behave in such a childish manner. Anna wasn't here, so the only possible culprit had to be...

It was his turn to smirk now. Albus Dumbledore had truly been a great man and wizard.

"You're on!" He cried, grabbing a fistful of snow. He marvelled at how it was the perfect consistency for making snowballs, but not too long... Elsa already had a head start on the ammunition front.

It was surreal, really. It had only been a handful of hours since the funeral, yet already the area near Dumbledore's tomb was being filled with laughter.

Unwittingly the two were fulfilling one of the deceased's greatest desires:
That the children he had failed to protect would be able to smile and play once more.

If only for a short while at least.

Fin.