Hogwarts castle was more than merely a school. Its ancient walls which have stood for centuries were home to many secrets still waiting to be uncovered. Some might say the castle itself was a mystery, with its many twisting corridors and secret passageways. Indeed, it was uncertain if the castle had ever been explored in its entirety. Scholars had long postulated that not even the school's founders knew Hogwarts completely, as there were legends that each founder had established at least some secret area within the castle, unknown to the others, so that no one person had ever known all the secrets the school had to offer.

Over the course of numerous centuries and even more hundreds of thousands of students, the castle would occasionally house a student, such as yourself, more curious than most, who took it upon themselves to learn as much as possible about its many ancient mysteries, wandering the old halls in search of some dark secret long forgotten. For most it was merely a game, an entertaining challenge to locate as many of the school's secret passageways as possible, of which you knew twenty-seven. For others more academic, it was in search of knowledge, of ancient magics lost to time. And for a very select few, it was in search of the legends. Of Salazar Slytherin's fabled Chamber of Secrets. Of a mysterious room somewhere on the fifth floor of the castle, that seemingly appeared and vanished at random. Of the Cursed Vaults, rumored to hold some unimaginable power, granted only to those who could overcome the curses inside.

It was the last of these that had taken your brother from you. You could remember how determined he was, how he would return each year for the summer holiday, more and more fixated on finding the vaults. Each year it seemed you lost more and more of the brother you once knew, until eventually, you lost him entirely. Even now, people still remembered the stories in the Daily Prophet, the name Jacob (L/N) surrounded in infamy. His obsession led many to call him mad, a label that you had inherited when you began your first year at Hogwarts. A label that only stuck as you followed in your brother's footsteps, desperate to find him.

As a result of your search for the Cursed Vaults, you had seen more, uncovered more than any of your classmates. Secret passages, hidden rooms, you had right to believe you knew more of the castle than any other student, and most of the faculty, except Dumbledore himself, of course. It was in your third year while searching for information about the vault of fear that you made a most peculiar discovery.

Locked away in some dusty room you had never been in before, hidden in some dark corner of the castle you hadn't even known existed. The room was completely empty except for a large ornate mirror. It was at least ten feet high, its golden frame ending in two clawed feet, like bird talons, that held it off the ground. Carved along the top of the mirror's intricate frame was a most peculiar inscription: Erised stra ehru oyt ube cafru oyt on woshi. The mirror itself, though lavish and grand, was nothing special. It was what you saw in it that caused you to start. Though when first examining it you saw only your own dusty reflection, when looking in the glass properly, you saw something which caused your heart to quicken.

You saw your brother, Jacob, alive and well. He was standing next to you, smiling and ruffling your hair. He looked just like you remembered him, before the Cursed Vaults consumed his every thought. You pressed your hands up against the glass, hoping to fall through and into the arms of your older brother.

You got little sleep that night, the image of your brother flickering behind your eyelids every time you closed them. You returned to the mirror again the next day and were once again greeted with the reflection of your smiling brother. You stared at the glass for at least an hour before realizing you had class, and that Professor Snape would be most displeased if you were to arrive late.

The next time you visited you brought Rowan with you. They were far more knowledgeable about these sorts of things, and you thought perhaps they might be able to offer some insight as to how the mirror worked. Allowing Rowan to stand in front of the mirror, you asked what they saw.

"I see myself." They said slowly. "But, I'm older. I've graduated Hogwarts and, blimey, I'm headmaster! The youngest headmaster at Hogwarts!"

You quickly rushed to Rowan's side to see what they saw, but it was just you and your brother. What was even stranger, even though Rowan was just on your right, they did not appear in the mirror's reflection. It was most curious, and Rowan could offer no insight.

By your sixth visit you had come to some conclusion about the mirror. It did not depict reality, neither the past, present, nor future, this you were certain of. Having also brought Ben to the mirror, you determined that the reflection changed to suit the person or persons gazing into it. The inscription held the key, you were certain of it. You had memorized the phrase but no matter how long you lingered on it, you couldn't make any sense of it. Not even Rowan could decipher the writing, claiming it was in no language they recognized. It was not until months later that you finally solved the perplexing mystery. It was after all a mirror, and it was a mirror's job to reflect. To reverse. Taking the inscription, you flipped it, and then all was revealed. The Mirror of Erised revealed the onlooker's deepest most desperate desires of their heart.

Having solved the mystery, you told yourself you would never again return to the mirror. You had more important matters at hand, and though the mirror gave you your brother, it wasn't truly him. The only way to truly get your brother back was to find all the Cursed Vaults and staring into a dusty mirror would not help you accomplish this.

Despite your promise, you occasionally found yourself returning to the room and staring into the looking glass. It was never for very long, and only when you found yourself in need of encouragement. Finding the vaults was a long and tiresome process, bearing many obstacles and complications. Whenever you were at risk of running out of energy, you relied on the mirror and the image it presented to remind you what it was all for. To give you the motivation you so desperately needed to continue in your journey. With its help you managed to successfully locate and enter the vault in the Dark Forest, breaking the sleepwalking curse, and bringing you one step closer to your brother.

As your fifth year rolled around you were forced to go on without assistance from the mirror. Not because you had forgotten your way to it or because it had been moved, but because there were more important matters at hand. Penny's younger sister, Beatrice, fell prey to the most recent curse. A fate worse than death, she found herself trapped inside a portrait, isolated from the rest of the world as she slowly faded from existence. Penny quickly began to unravel, going mad with fear at the thought of losing her sister. Seeing her in such a panicked state was all the motivation you needed. Losing her sibling would destroy her, and you refused to allow Penny to share your fate. Finding the next vault and freeing Beatrice became your primary concern, there was no time to worry about a reflection in a dusty old mirror.

Though it was hardly the time with everything going on, you found yourself early in the year confessing to Penny that you had feelings for her. Feelings that extended beyond the realm of friendship. Distracted by her sister's wellbeing at the time, Penny had had difficulty processing your words, and was too preoccupied to give your proposition any thought. She had promised though, that once Beatrice was safe, the two of you would talk. That had been nearly a year ago.

In the end, you had managed to enter the vault and break the curse that had turned Beatrice into an oil painting and free her from her enchanted prison. Penny had been over the moon of course, overwhelmed with a sense of relief and joy, tears freely falling from her eyes as she embraced her sister whom she had feared she might lose. Extremely glad to see Penny reunited with her sister, some part of you, perhaps the more selfish side, couldn't help but look forward to discussing your feelings towards one another with Penny. Of course, you hadn't expected to discuss it immediately after rescuing Beatrice, but you had hoped the two of you might talk within the few stress-free weeks preceding the summer holiday. But Penny's joy at having her sister restored was so great it seemed to push all other thoughts aside, including your promised conversation, and you just couldn't find the heart to take her away from it, even if just for several minutes.

Going home that summer had been especially difficult. Not only because it separated you from Penny and a much-needed conversation that never happened, but also because of what the year had held. Seeing Penny with Beatrice only served to remind you how much you missed Jacob, and whereas Penny returned home with Beatrice safely by her side, you returned facing the concept of another lonesome three months, spent in isolation in your room as you prepared for the challenges that were sure to face you the following year.

Sixth year rolled around, and you felt lonelier than ever. The prospect of spending another year searching tirelessly for the next vault was not an appealing one, and you once again found yourself running on fumes. The idea of closing your eyes and sleeping for several days grew more and more tempting until eventually, against your better judgement, you found yourself returning to the dusty room in the secluded corner of the castle.

Just a few minutes, that was all you needed. Just a few minutes of seeing your brother's smiling face as he mussed up your hair to remind you that it would all be worth it in the end. Entering the room your eyes drifted over to the mirror standing in the corner. Slowly, you approached it, staring into the glass, eager to see your brother, only, the image that was reflected back at you was not one you were familiar with. Certainly, your eyes were playing tricks on you, your tired brain presenting some sort of hallucination. Blinking several times, you rubbed your eyes before looking once more into the mirror.

Your eyes weren't mistaken. In the mirror you saw not your brother, but Penny. Her eyes were closed in a blissful smile, her head rested against the bottom of your shoulder as her arms wrapped around your own. Your own head was rested atop hers, face nuzzled in her blonde hair as you inhaled her scent. Not tearing your eyes away, you slowly sat cross legged on the floor, staring up at the reflection in front of you, mouth open in wonder. As you continued watching, the you in the mirror slowly brushed the hair from Penny's face, and you captured her lips in a passionate kiss. She stood on her tip toes, arms locked around your neck as she pulled you down so she could better access your lips. Your own arms wrapped securely around her petite frame, one hand resting on the small of her back, the other tangled in her brilliant golden locks that cascade down her back like droplets of the sun.

You continued to watch with longing eyes, and the longer you watched the more you wished the reflection were reality. You gorged on the sight before you, your heart becoming full, but at the same time, very heavy. You lost ten house points walking into potions class late.

You started spending more time in the dusty room, hours passing by as you gazed wistfully into the mirror. You knew it was unwise, the mirror only furthering your mad obsession and longing, but you couldn't help yourself. You still missed Jacob, of course, but he and the vaults just seemed so distant, whereas Penny was so real, so lifelike.

It eventually got to the point where you were spending more time in front of the mirror than with your friends, and they were beginning to grow concerned. Rowan and Ben cornered you one day, asking where you had been. You brushed them off with a vague answer, simply saying you'd been busy. Andre was concerned for your personal appearance, stating that every day you looked more and more shabby. Charlie said you were sure to lose your Prefect's badge if you kept up the way you were going. Their words meant nothing to you. The only thing that mattered anymore was Penny. Funnily enough, in seeking her out, you only pushed her further away.

You were addicted now. Every free second you had was spent in front of the mirror. Your grades were slipping, and you hadn't slept more than three hours a night in the past two weeks. Your friends were becoming increasingly concerned for your wellbeing, but you simply wouldn't listen to any of them. It was only Penny that could get you to do anything now. You would only eat at her behest, only sleep to ease her mind. But when she wasn't looking, you were back in front of the mirror.

It was now mid-February in your sixth year, and you once again found yourself neglecting both your studies and Prefect duties, sitting in front of the Mirror of Erised as you gazed longingly at Penny wrapped in your arms as the two of you stood in a loving embrace.

"Is this where you've been all this time?"

You turn at the sound of her voice, pulling your mind from the image in the mirror.

"Penny?" You say in surprise, jumping to your feet. "What are you doing here?"

"We're concerned about you (F/N)." She says, her blue eyes full of worry. "All of us are."

"Did you follow me here?" You ask somewhat accusingly.

"I may have." She says, looking down at her feet. "But it's only because I've been worried sick about you." She adds hastily.

"I'm fine Penny. Really, I am."

"Don't lie to me (F/N). I know you're not fine. You don't pay attention in class anymore, you've stopped eating, and Rowan told me you sneak out of the dormitories in the middle of the night."

You curse Rowan internally, even though they've really done nothing wrong.

"So is this it then?" Penny asks, looking at the Mirror of Erised. "Is this what's been distracting you lately?"

You sigh and nod.

"What is it?" She asks.

"A mirror." You reply.

"Obviously." She laughs, rolling her eyes. "But what does it do? I mean, it must do something for you to keep spending so much time here."

"It's called the Mirror of Erised." You explain, figuring it won't hurt. Besides, it's not like she'll ever know what you see when you look in it.

"What's so special about it?"

"Well," You say, "it shows you things."

"Like what?"

"Things you want."

"What, like money?"

"Maybe." You shrug. "It depends on the person."

"It depends on the person." Penny repeats. "How so?"

"Well, for instance, when Rowan looks in the mirror, they see themselves as the headmaster of Hogwarts. The youngest ever headmaster. And Ben sees himself brave and unafraid."

"Rowan and Ben have been here?" Penny asks, more caught up on that than the phenomenon of the different reflections.

"Just the once." You say. "And that was three years ago."

"So, this mirror," Penny says slowly, "it shows people what they want? But not just anything, only what they want the most. The truest desires of their heart?"

You nod. Penny laughs and you look at her. Still standing next to you, she's looking over her shoulder at the mirror.

"What is it?"

"You're pulling my leg." She laughs, turning back to face you. "I don't see anything."

"That's because you're not looking at it properly." You say.

From behind, you place your hands gently on her shoulders and carefully guide her over to the mirror. Still with your hands on her, you look down at her intently, carefully watching her brilliant blue eyes. Her brow furrows, nose scrunching up cutely as she frowns in confusion.

"I still don't understand." She says, shaking her head. "I-It's just a mirror."

"No, no it's not." You shake your head and point at the mirror. "Look closer."

Penny does as you say, squinting and leaning forwards slightly as she looks closer.

"(F/N), I-I still don't... I mean, it's just..." Her voice trails off.

"What?" You urge.

"I-It's nothing. Only, I still don't see anything." Turning around, she looks up at you. "I just see us."