It seemed to Elsa that the days were longer now than they used to be. When she was a child – or at least, before Anna's accident – it felt as if sunlight only streamed for a matter of hours before the moon ascended. Now, when viewed from the frosted windows of her room, it appeared that years could pass before the sun would set.

But it wasn't the passing of time that had changed since those short summers. Sure enough, to the children she watched from her window, the days were just as brief; it was her that had changed. She used to be so busy with Anna that time simply flew past her, but she knew only too well that those things were impossible now. She was alone now. That was it.

Resting her elbows against the windowsill, she clenched her fists and watched hopelessly as tiny flourishes of ice crackled against the glass. She had been taught for as long as she could remember that her powers were a curse to be hidden, but she indulged in them for a few moments, and allowed the flourishes to grow and engulf the whole windowpane. With one pale finger, she traced a swirling pattern in the frost, before turning away with a faint smile.

A gentle knocking against the door caught her attention, and for a moment, she froze. Her heart sank as she imagined Anna standing on the other side, waiting in the corridor for a response she would never get – not that Elsa was withholding it to be cruel. Before she could mourn the loss of their friendship, as she had often wiled away her long hours doing, she heard her father's voice.

"Elsa?" he called.

"Yes, father?" She crossed the room and reached for a pair of silky lilac gloves on the side-table. They had been a gift from her parents for her sixteenth birthday, and she recalled painful memories from the day as she pulled the material over her fingertips. Then, the gloves had been a burden – one that she had accepted gracefully but quietly resented – and she hadn't been able to stop herself from cracking slightly beneath the pressure of her parents' approval. She had replaced her worn, dusty gloves with the new pair before running out into the courtyard and sheltering beneath the arches, hiding her sobbing from the worried servants. Now, they were a duty, and she barely gave a thought to what they represented as she opened the door to her father.

"Good morning, Elsa," he said warmly as he entered the room. She carefully shut the door behind him out of habit, and turned to face his eyes to see concern in them – he too had focused his attentions on the lilac gloves. "I do hope that you will approve of our gift choices tomorrow," he added to his greeting cautiously.

"Don't worry," she uttered stiffly in response. Conversation with her parents was always stilted; between them stood the division of her powers. The powers stood between her and everybody else, but she felt it most painfully with her parents, as she knew that their precautions were necessary but key to her imprisonment in the castle. "That was two years ago. It won't happen again."

He smiled. She spotted a certain amount of pride behind his eyes. "I'm glad to hear it," he responded, plucking up an ornament from her side-table and examining it for a moment. It was a rounded ball, just large enough to fill his palm as he rolled it between his fingers, decorated with intricately-painted snowflakes. "Did your mother buy you this from the market?"

"It was a gift from Anna," she replied.

Her father paused for a moment, before putting the object back on to its gilded stand. "It's pretty."

Elsa swallowed, hoping to stop her throat from tightening with the threat of tears. It wasn't like her to be sentimental, and she silently scolded herself for the moment of weakness. "I know." Like her father, she had examined it closely, but had spent hours poring over the tiny flecks on each snowflake. Her sister was a budding artist it seemed, as each shape was different and beautifully unique; it had been a gift, delivered to her by a kind young servant a few months ago who was friends with Anna. She hadn't given the young man a gift in return to send back to her sister, but she had wanted to. Just seeing the ornament in her father's hands made her long to even more.

Her father had been watching her as her face softened with thoughts of Anna, and so she collected herself quickly and resorted back to her well-practised mask of calm confidence. "The castle's going to be a little busier for a few weeks – we have a trade visit from the royalty of Groveston." His words were gentle but not forgiving; they were both well aware of their responsibilities in the family, and hers was not to have contact with Anna. He could not encourage her to betray that promise.

She had spent years memorising each detail of the map hung on the wall of her room, but she feigned ignorance just so that her father would stay for a little longer. "Where's that again?"

He shot a sideways glance to the map on the wall. "It's just a few miles down the fjord. It's not a huge trading partner – they sell us some of the salmon that swim in the rapids by their village, and we give them some woven clothes – but we have to keep up our relations with these places."

"Is that why you're leaving next week?" She was grateful for a visitor, but she couldn't help her tone from growing hostile with the words. Her parents were due to depart on a long voyage to a foreign territory, and despite her pleading with them to stay for a little while longer, they were already preparing for the trip.

He sighed, and softly extended a hand towards her face to tuck back a stray strand of hair. "That's partly why we're going, yes," he said quietly. "However, we also have some promises to keep over there."

"You know that I have a bad feeling about this trip."

"I know." He let one hand rest on her shoulder. Her muscles were tense, and a small blossom of ice appeared on the cuff of his jacket, gleaming white against the navy of the material. Elsa withdrew herself from his touch immediately and shrank back towards the wall of her room, hoping for a shadow to swallow her up and hide her from her father's disapproving gaze.

She didn't need to explain that it was getting worse. There was a mutual understanding between them that her powers were strengthening against her will, an unspoken but acknowledged truth that they chose to ignore. The icy blemish on his jacket was just another reminder of that, and though he could have reprimanded her for letting her powers show, he simply lowered his hand from the empty air where she had been standing and headed for the door.

Showered in the full beam of the morning sun, the gilded embellishment of his robes glittered, and he once again became the King instead of just her father. As the title demanded, she bowed her head with respect when he reached for the door handle. "I just came to warn you about the visitors," he called back to her. "Remember to be careful."

And with a gentle tap, the door to the outside world was closed again, and she was left in the shadows.

Alone, she had time to think. Eighteen. The word sounded so strange in her mind – it felt like freedom, like it should represent a rush of independence or the unlocking of binding chain, and yet it still rang sour against the confining walls of her room. With age, her freedoms had gradually increased – at least she could leave her room sometimes now, though it was usually at night when Anna and the servants were asleep. Still, she bitterly defined herself as a prisoner, and returned to her window as if seeking a glimpse of the world outside a cell.

She watched longingly as the ships tilted on the waves. If she stretched over the windowsill, she could see down to the docks, where the palace guards were helping to unload crates from a huge travelling ship. Her eyes were drawn to the figurehead at the bough of the ship, which was carved from a strong wood but seemed to be painted with gold detail. The distance restricted her, but she picked out the eyes and mouth of a face carved into the wood, and slowly she worked out the shape to be a woman's head, staring sternly with an empty gaze towards the horizon.

It seemed that everybody was down by the ship, heaving crates on to the docks and greeting the Groveston visitors. Even in the bustle of the excited crowd, she could spot the figures of her parents and sister, surrounded by guards. Elsa couldn't hear a sound coming from the corridor – all the servants were probably busy in the kitchens in a mad rush to prepare a feast for the newcomers. The castle was practically empty.

In an empty castle, there would be no witnesses to a little bit of magic.

And the idea had bloomed in her mind before she had the will to stop it. The thought was dangerous, yes, and getting caught would be disastrous, of course – but despite every part of her mind that told her an adventure could never end well, there was just enough of her heart that was yearning for just that to overpower everything else and lead her to the doorway. Her parents never locked the door now, which she had always considered to be a liability until today. Today, it was a blessing. It was almost a sign that she had to see what was out there.

To see the palace in daylight! Her fingertips twitched excitedly at just the idea of it, sending little shoots of hail into the carpet. She guessed that she wouldn't have long before the crowds wound their way back up to the castle, but it was enough. A second would be enough – more than that would simply be a gift.

Elsa was at the door. Her hand trembled as she reached for the handle. She repeated to herself very carefully that a second would be enough. She was wearing gloves, and so she told herself that she would be safe. It was just a second outside. If no one was around, then what harm could it do?

As her fingertips touched the metal of the door handle, comfortingly cool against her palm, it crackled gently with the spread of ice. So the gloves may not have been as effective as she had hoped, but she had already pursued the idea beyond the point of not following it through, and so she just told herself not to touch anything. She turned it, slowly, shakily, and opened her eyes to a bright new world that had been closed to her for so long.