Author's Note: This is UN-BETA'ed (please forgive me if it sucks)!

.

Slipping into Killian's dorm room, Emma silently closed the door behind her and looked around. As before, the right side of the room was bare and vacant, with an undressed mattress in the bed frame and an empty desk and dresser. It had been Graham's part of the room, and now it was unused.

The left side of the room, however, was occupied. A pair of worn trainers and a broom lay discarded near the door. Jeans and jumpers hung out of the drawers of the bureau. A worn, folded piece of parchment and Killian's unmistakable wand (cedar, 13in, unyielding) sat on the desk beside the bed. Looking carefully, Emma found the shimmering outline of Killian's invisibility cloak hanging from one of the posts of the bed frame.

Emma considered checking the map to see if he was really in the bed. It somehow seemed more invasive than just pulling back the drapes. So, taking a deep breath, Emma padded across the rich carpet to the massive bed. She reached out and collected a handful of the thick, velvet curtains. Drawing them aside, she peered into the darkness, letting her eyes adjust and take in the form of blankets and pillows and a fitfully sleeping Hufflepuff.

His hair was a complete mess, sticking out in adorable disarray. His brow was furrowed, and he tossed his head back and forth. She'd seen him like that before, in the infirmary, and her instinct was the same: she wanted to soothe him. She could yell at him for being an idiot later.

Slipping into the bed, Emma let the curtain fall mostly shut behind her. She slunk across to where Killian squirmed and laid a gentle hand on his chest. Fingers immediately encircled her wrist, and then she was tugged forward and rolled. Rather abruptly, she found herself lying on her back, with a warm body lying over her, one of his knees resting between hers.

"Emma," he breathed, his voice slurred. A stubbled chin brushed against her neck. His hand came up to cup her cheek for a moment before he threaded his fingers into her hair. He moved against her in a sinfully delicious way.

"Jones," Emma said, her voice coming out airy. "Killia—"

He cut her off with a kiss, pressing his mouth hungrily to hers. Emma's eyes rolled back into her head and her toes curled at the way he molded himself to hers. For a moment, she couldn't remember why she'd fought this sort of thing.

Oh, right, because guys she thought she could trust tended to disappear.

Like Killian had.

Emma shoved the amorous Hufflepuff off of her. He made a frustrated noise and came back over to her, but she just shoved him away again. He whined, and then he paused and inhaled sharply. That's when Emma knew he'd realized he wasn't dreaming.

"Emma?" he said in a completely different tone. His voice shaking and just slightly aghast.

"Jones," she replied, letting the name out in a huff. "What the hell?"

"What the—" he muttered, then he seemed to do a doubletake. He let out a little growl. "You snuck into my room, Swan—into my bed—and then you take that tone? Pardon me for assuming a guest might, perhaps, announce herself instead of… of… What are you doing here?"

"I could ask you the same question!" Emma hissed.

"I was sleeping!" Killian shot back.

"What are you doing at Hogwarts?" Emma demanded.

"I'm—" Killian started to say something but he cut himself off. His tone turned to ice. "It's none of your business, Swan."

Emma tried not to let the words hurt her. She'd thought he trusted her. She'd thought they had… something. Feeling betrayed and small, she shielded herself with anger.

"Oh, right. Of course," she said sarcastically. "That's why you keep showing up outside my classes and stuff. You certainly didn't want me to find you."

There was a second of silent before he replied.

"Perhaps you've been imagining things, darling," he taunted in a silken voice. "I'm flattered to hear you see my face everywhere you go."

Emma scowled at him.

"Cut the crap, Jones," she snapped. "What are you doing at Hogwarts?"

He growled again.

"Bloody hell, Swan!" he swore. "Give me a moment to collect myself, would you? I've been awake for all of ninety seconds."

"You've been on campus for two months!" she shot back. "You should have already thought about it!"

She let out an angry huff of breath, yanking her fingers through her hair.

"How is this room even still free?" she continued. "Why aren't their first year students assigned here?"

"Because it's my room," he said not quite politely. "They wouldn't reassign an occupied room when I still had the chance to show up."

Emma couldn't help but nod, realizing he was right.

"And once the new first years had been assigned," Emma said, following the logic, "this room would just be vacant."

"Aye," he said.

"Okay," she said, "so the room was free. But why are you here if you're not taking classes?"

Emma felt him shift his weight. When he didn't reply, she angrily yanked the curtains aside so a little more light trickled in. Turning back to him, she found he looked… miserable.

"What?" she said. She intended to snap the word, but it came out more empathetic. "What's going on?"

He turned away.

"Damn it, Killian," she said. "Why are you shutting me out?"

His shoulders slumped, but he said nothing. She could feel the misery coming off of him in waves. Whatever his burden, it was weighing heavily. She frowned as she watched him curl a little deeper into himself. Then she sighed.

"After everything you've done for me," she said softly, "why won't you let me help you?"

He slowly turned to face her again, his expression sad but tentatively hopeful.

"Emma…" he whispered. He reached for her with shaking fingers. She caught his hand and brought it to her cheek. She knew him well enough—hell, she knew herself well enough—to know how hard it must be fore him to be vulnerable. They were so much alike.

She scooted across to him and collected him in her arms. He wrapped his arms her waist, laying his cheek against her hip. She stroked his hair.

"Just tell me," she said softly. "Whatever it is, you don't have to face it alone."

His shoulders shook and he squeezed her tight. He took a breath, but it broke, turning into a stuttering sob. Emma held the him while he quietly fell apart, soothing him with light touches and whispered words. Finally, he pulled back, discretely wiping his face on his sleeve before turning to face her again. His expression tightened, and he met her gaze with red-rimmed eyes.

"Are you certain you wish to know?" he asked.

She took one of his hands in hers.

"Yes," she said, nodding once and squeezing his fingers.

He nodded in reply, taking a deep breath and setting his shoulders. He let his eyes unfocus as he cast himself into his memories.

"My father was a Death Eater," he began in a low, hollow voice. "He was always a coward, so he didn't fight when the Dark One appeared; he dropped to his knees as swore allegiance. He served the Dark One for years, disappearing from home for months at a time. I don't remember much of it—I was quite young—but Liam was older, and he… he had to take care of me."

He took another deep breath.

"And then one day he sent an owl," Killian continued. "The message was short; it said, 'Betrayal. Get out. I'm sorry.' So Liam obeyed, and we fled our home with whatever we could carry. Liam was still underage, so we could use no magic… We found out the next day in the papers that our father was dead. They said it was the Killing Curse… We knew who did it."

Killian paused for a moment, and Emma stayed quiet, listening intently.

"Liam became obsessed," he went on. "He was determined to learn what had happened. He found this woman, Milah, who was connected to the Dark One somehow. Together, they did research and tried to hunt down any information they could on what happened to our father."

He paused again.

"He… wasn't careful enough," Killian said, his eyes taking on a haunted look. "At Christmas, they came for us. We ran, again. This time Liam was old enough, so he fought back. We had the cloak, then, and Liam threw it over me. I saw the flash of green, but I didn't see the face of the man who murdered my brother."

"I'm so sorry," Emma said.

Killian gave her a sad smile and then took a deep breath.

"There wasn't much I could do," he said. "I was put in a home for boys, though it was a wizard place, unlike your Muggle residence. I had nothing to guide me, so I shut away any ideas of trying to pursue them. Liam hadn't shared his information with his kid brother, you see. I knew next to nothing until I came of age."

He licked his lips.

"When I turned seventeen, I inherited our family home," he said. "I didn't rightly care, but I knew Liam would have wanted me to at least go and see it, so I did. I found a letter shoved under the door. It was addressed to me and told me that a parcel was waiting at the Muggle post office. The notice was dated from before Liam's death, but I went anyway. By chance, they still had the parcel and a letter. The letter was from Liam… It said… It said if I'd received it, then he must be dead… And that he knew I'd want to know what he'd known, so he'd left me what he had. The parcel contained all of Liams notes about our father and his death. I've been pouring through them since then… And, I found Milah. Liam had an address for her, but the Death Eaters got to her shortly after we met… She… She's gone, too."

He paused again, taking another long breath.

"I've learned things—things about the Dark One," Killian said, his voice and expression turning fervent. "I think I've found a way to defeat him."

"That's impossible," Emma said. "He's immune to both magical and mundane attacks. The only reason he hasn't conquered everything is that he seems preoccupied."

"Aye," Killian said, nodding, "with his son."

"The Dark One has a son?" Emma said, eyes going wide.

"Aye," he repeated. He paused, searching her face. "His name is Neal Cassidy."

Emma felt like a caldron of ice water had been dumped over her.

"What?" she exclaimed with wide eyes. "No. That's impossible."

"I'm sorry, Swan," Killian said. "I tried to keep you out of it."

"I did not date the Dark One's son," Emma protested, shaking her head violently.

"I'm afraid you did," Killian said. "But if it makes you feel better, I don't think Neal is involved in his father's… work. From what Milah told me, he came to Hogwarts to get away from what his father was doing."

Emma chewed on that, trying to remember if Neal had ever said anything about his father while they dated. They'd only been together for a few months before he'd disappeared.

"That's why he left so abruptly," she murmured.

"Highly possible," Killian said. "I'd wager something happened that drew him away in haste."

Emma shook her head again.

"Okay, whatever," she said. "Even if Neal is the Dark One's son—which I don't believe—that doesn't explain why you're here."

Killian nodded.

"The Dark One was once a student here," he explained. "I'd hoped I might learn more about him if I could research his early years as a wizard."

"The Dark One went to Hogwarts?" Emma said incredulously.

"Yes," Killian said emphatically.

He believed what he was saying.

"That's ridiculous," Emma said. "How could no one else know that?"

"Well, he wasn't called 'the Dark One' as a student, Swan," he said dryly.

"So, what's the Dark One's true name, then?" Emma asked, still disbelieving.

"I… can't tell you," Killian said carefully.

"Right," Emma replied, drawing out the word and giving him a patronizing look.

"Really," he said with wide eyes. "There is a taboo on his name. I believe that's how the Death Eater's found Liam. He must have said the name aloud."

Emma rocked back. A chill ran down her spine. It would make sense for the Dark One to make it difficult for people to look into his past, especially if he had loved ones or family that could be exploited.

"What's more," Killian went on, "I think he has created a horcrux."

"A horcrux?" she asked, blinking at the unfamiliar word. "What's that?"

"It's the blackest kind of magic," he explained. "A horcrux is a phylactery—A box for one's soul. While the Dark One's soul in in the horcrux, his physical body is nigh invulnerable. To destroy him, we'll have to find the horcrux."

"So, we're looking for a box?" Emma said dryly, raising an eyebrow.

"I don't know so," Killian said, shaking his head. "It's magic, so it doesn't have to take the shape of a box. It could be anything, really, though I'd imagine it would be an object that had some sort of significance to the wizard."

Emma nodded.

So, you're trying to learn more about the Dark One to figure out what he might use for a horcrux?" she said.

"Exactly," he replied.

"What about the taboo?" she asked.

"Well, that's a clue, too," he explained. "You see, when you enchant a taboo, you have to offset the word or phrase you've chosen with another, and the other word or phrase becomes the… ah, answer to the riddle, if you will. So, if we can learn the answer, we can undo the taboo, which will weaken the Dark One."

"How will that weaken the Dark One?" Emma asked, frowning.

"He's put a taboo on his name," Killian said. "That means he's given his name power. He can harness that power to strengthen his magic."

"But if we can find the killswitch word," Emma said, "we'll cut off that supply of extra power?"

"Precisely," he said with a nod. "And the 'killswitch,' as you called it, has to be related to the thing that has been made taboo."

"So, it's related to his name somehow," Emma mused. "But what does that mean? How can a word or phrase be related to a name?"

"Well, I don't know," he said sheepishly. "But I intend to find out. Then I'll need to find the horcrux. I don't want to just break the taboo and have him know someone is after him. I'll need to break the taboo and the horcrux at the same time. They he'll be mortal again."

"Then what?" she asked.

"Then I'll destroy him," he said in a low, dangerous voice. His eyes flashed with conviction.

Emma chewed on her lip for a moment before speaking.

"So, what have you got so far?" she asked.

"I've got clues and hints and whispers," he said with a sigh, scratching behind his ear. "I haven't found much, truly. I… I thought I could do it on my own…"

He looked down for a moment before meeting her eyes again with sadness and shame in his gaze.

"I could use some help," he continued in a small voice. "I just never wanted to put you in danger, Emma."

She gave him a little smile.

"If you expect me to stand back and let you fight the Dark One alone, Killian," she said, "then you don't know me very well."

He chuffed lightly, looking at their entwined hands with a tiny ghost of a smile. When he lifted his head to meet her gaze, his expression was intent.

"Are you certain, Emma?" he asked, searching her eyes and squeezing her hands.

"Yes," she said immediately. "Let's take down the Dark One."

.

Reviews are what I see in the Mirror of Erised.