A/N: Since it's been a while since the last update, let's review where we left off, shall we?

Professor Davidoff is illegally combining muggle science and magical remedies in an attempt to 'cure the incurable'. He's testing these experiments on students, and he's killed Liz (for reasons unknown). Meanwhile, Rae and Tori are both up to something (separate somethings) involving Davidoff and their respective mothers. Chloe followed Derek into the grounds, was attacked by a swarm of ghosts, banished them, found out that Derek is in fact a werewolf, found out that despite the risks, Derek has been taking the potions Davidoff is making for him, and helped Derek through a Change in which he transformed into a real wolf, rather than the usual Harry Potter-style werewolf. *comes up for air* Still with me? Then allow me to present Chapter Nine!

Chapter Nine

Chloe woke to find her face pressed into a thick wall of fur.

For a moment, she allowed herself to enjoy the warm, safe lethargy that came with waking. Her eyelids drooped lazily closed again as she nestled into the warm fur of the rumbling creature she rested on.

Then she remembered her surroundings and her eyes snapped open.

"Derek," she said tentatively, her voice higher than usual. "That still you?"

The wolf rumbled again, bushy tail thumping against the floor in apparent frustration. She looked at him. Really looked. She must have rested for a few hours at least, because the room was lighter now, and she could see him clearer. There was no doubt in her mind that this was Derek, not some mindless monster. She'd heard all sorts of horror stories about werewolves in her Defence Against the Dark Arts lessons, but couldn't reconcile those words and images with the black wolf she'd fallen asleep beside. The wolf with those otherworldly green eyes she knew so well set into its long, thin face.

He whined a quiet, tense sound and Chloe drew back. "What is it?" she asked quickly. "What's wrong?"

The wolf opened his jaw, baring his teeth. A strangled growl escaped his throat and he huffed in frustration, slumping to the floorboards in defeat.

Chloe giggled. "What's the matter? Wolf got your tongue?" It was admittedly a lame joke, but at the wolf's attempted glare, she couldn't help but laugh harder. He raised himself up on his haunches and began to pace the room, occasionally swinging his muzzle in Chloe's direction, as if constantly surprised to see her there.

"Why are you cooped up in here?" she asked as he paced. His constant movement was making her restless. "I mean… you're not dangerous or anything, are you?"

Derek stopped pacing. He swung his snout left, then right, in an awkward approximation of a head-shake.

"Well then – oh," she said, as the final pieces of the puzzle slotted into place. "This is your first change since you started taking Davidoff's potions, isn't it?"

The wolf stared at her for a long while before he lowered his head slowly. Yes.

"So you've been coming down here ever since you started your Changes?" She looked around the dusty room with its rotten floorboards and broken furniture and felt a rush of sympathy towards Derek. She couldn't imagine subduing her nature to hide a secret so monumental. Werewolves were wild, dangerous creatures. Confined, a werewolf became scared and volatile. And yet, Derek had suffered through that fear, deliberately confining himself month after month to keep his fellow students safe. The sympathy she felt transformed into something else, a twisting warmth in her chest when she thought of Derek's surprising kindness. She breathed a sigh of relief that Derek's Change tonight had been different… and then quickly reminded herself that Davidoff could have just as easily killed Derek as helped him. Whatever Davidoff had planned for them, he wasn't conducting these experiments out of the kindness of his heart.

"You and I need to talk," she said out loud. "Once you've changed back. No secrets this time. If you want me to trust you, you have to tell me everything. Okay?"

The wolf looked at her, its – no, his – eyes gleaming like a cats'. He bowed his head again. When he looked up, something in his expression moved her to crawl over to his side again. Sorry, his eyes seemed to say. I'm sorry I didn't trust you. I do now.

She rested her hand on his back, burying her fingers in surprisingly soft fur. His spine had changed shape but she remembered touching him like this as the Change began – her hand providing comfort and support as his back tensed, sweat coating his skin. For some reason this memory brought a fierce blush to her cheeks and she pulled her hand away.

The wolf looked at her questioningly, his head cocked to the side. She looked away and started talking, stumbling over the words, but determined to get them out. He had promised her honesty – now she would give him the same.

"I… summoned something tonight," she admitted. "A dead cat. I'm not sure how and I know it shouldn't be possible without complex rituals and dark magic, but… I raised it and forced it to do my will. That's bad, right? If anyone finds out, I'll be expelled. And I'm not even sure how I did it. What if I can't control it?"

Derek sat back on his haunches, and then leaned forward until he was lying on his stomach, his head inches from her lap. His eyes never strayed from hers as she spoke.

"I thought Davidoff's potion had worn off," Chloe said. "But maybe it didn't just block my powers. Maybe it awakened them somehow."

But even as she said the words, she knew they didn't make sense. Davidoff's potion had weakened Derek's power. Although he'd kept his strength and senses, his Change was now more similar to an animagus' transformation than a traditional werewolf's monthly curse. And a regular wolf was far less powerful than a werewolf.

If Davidoff was deliberately weakening their powers, why had Chloe's abilities suddenly flared up tonight? She thought of her mother's necklace, still in her pocket after she'd broken it beside the Whomping Willow's swaying branches. It had protected her, kept her power hidden. Was this her natural power, then? And if so, why was her power so much stronger than she'd always been led to believe, so much stronger than even her Aunt Lauren had claimed it was?

She rocked forwards, cradling her head in her hands with a groan of frustration. Too many questions. Too many questions and not enough time to find the answers.

She felt something cold and wet nudge her hand. The wolf was still beside her, his snout at her head. He grumbled. You okay? She wiped her eyes and nodded.

"I'm okay," she said. "Just thinking. It seems like the potion Davidoff gave me was temporary. I don't think what happened tonight had anything to do with his experiments."

The wolf bowed his head again, as if in agreement. Then he rose and stumbled, knocking his muzzle against her leg. She laughed, but quickly stopped when he shook and let out a muted howl. This wasn't a clumsy mistake. He was changing back.

"Oh," she said in alarm, scrambling to her hands and knees. "I guess you probably want me to turn around this time, right?"

He huffed, his breathing already sounding laboured. She shifted so her back was to him, but stayed close. Gingerly, she reached backwards, gripping his paw in one of her hands. His breathing faltered and she felt him tense, but he didn't push her away.

This time, the Change seemed to go faster, though Chloe doubted it felt any easier. After a few minutes of listening to his agonising whines and clutching his hand as he dug his claws – and then, his nails – into the floorboards, she felt him slump down onto his side. His hand moved under hers for the first time since the fur had receded, and to her surprise, she felt him slowly entwine his fingers with hers.

She turned just enough to see his face. His cheek, shining with exhaustion, was pressed against the floor. His eyes were closed.

"Derek?" she whispered cautiously. She'd followed him into an underground passage, comforted him while he transformed, fallen asleep by his side and poured her heart out to him in the last few hours alone. And yet, now she found herself nervous and uncomfortable around him again. He opened his eyes and blinked up at her, not moving. Then he rolled onto his side and his hand slipped out of hers. He blinked again, his forehead creasing in confusion, like he didn't even remember clutching her hand in the first place.

She looked away again, acutely aware of his clothing predicament. She waited without moving while he stood and dressed, until she heard the clink of a belt and knew it must be safe to turn around.

Derek stood bare-chested, his jeans low on his hips. Chloe's mind froze for a few seconds as she stared up at him. She'd never thought of Derek as ugly exactly, but… well, she hadn't expected this. She'd hardly paid attention to his state of undress earlier, knowing that he was in trouble. Now that he wasn't halfway through a Change, she couldn't help but notice his physique. She'd never seen a guy their age so… well-toned. This was what he was hiding under his baggy clothing. He stretched, rolling his shoulders and she looked away quickly.

"Y-your shirt," she said shakily. "It's… it's a-around here somewhere…"

But by the time she'd turned back, he was already dressed in shirt, jeans and robes, tugging on the dark boots he'd kicked off when the Change first began.

"Bathroom," he said as he tied the laces. He didn't look up. "We have to get you to a bathroom."

She stared down at him, still feeling slightly dazed, like she'd been knocked in the head with Rae's beater's bat. "Um… what?"

He raised his head, meeting her eyes for the first time since he'd pulled away from her. "Chloe," he said in a gruff voice not dissimilar to the growls he'd made as a wolf, "You need to get to a bathroom. You're covered in blood."

Startled, Chloe looked down at herself. He was right, although 'covered' was a bit of an overstatement. If anything covered her pyjamas, it was dirt. She was filthy from head to toe. She'd also scraped her hands and knees some time during the night, and dried blood had stiffened her sleeves and pyjama legs.

"Oh," she said blankly. She must look a mess. For some reason, looking so tattered and grimy in front of Derek bothered her.

He stood up and looked at her. Wordlessly, he raised his wand and began to siphon off the worst of the dirt. It didn't help much. After a minute, he gave up and pulled off his Ravenclaw robes, holding them out to her.

"Come on," he said as he made his way to the passage entrance in two long strides. She followed, tugging the robes around her shoulders as she did so. They were too big and too heavy on her, but they were warm and smelled earthy.

They walked in silence up the tunnel that had taken them underground. When they reached ground level, Derek levitated a fallen twig and used it to immobilise the tree. She clutched the pendant in her pocket and looked around warily, but no ghosts followed them back to the castle. Her banishment seemed to be lasting at least for the night.

When they reached the main entrance, Chloe cast a new disillusionment charm on them both. They slipped through the door, discovering that the charms were still down.

"My dad," Derek explained in a hushed voice. "He's in charge of keeping up the wards tonight. Every night that I have to Change, he makes sure that I'm able to escape."

Chloe had assumed that Derek would lead them both back to the Hall, but the night wasn't over yet. He gestured towards the staircase and they both crept up it, mindful of the vanishing step that neither of them wanted to find themselves caught in tonight.

Derek led them to a statue of a confused-looking wizard on the fifth floor. She recognised this corridor immediately as the one Derek had taken her to just a few nights ago, when they'd been interrupted by the school-wide announcement to congregate in the Great Hall. He tapped the door beside the statue with his wand and muttered a few words she couldn't make out. Then the door was opening and he was ushering her inside and she found herself in the grandest, most opulent bathroom she had ever seen.

"Prefect's bathroom," Derek said by way of explanation. "Simon and I use it as a place to talk in private. And we both need to get cleaned up." He turned away from her and grabbed a cloth from the marble countertops circling the large pool in the centre of the room. He dipped it into the water and started scrubbing at his face.

Chloe marvelled at the size and beauty of the room for a few moments longer. It really was a masterpiece, and she felt a pang of sadness and jealousy at the thought that so few Hogwarts students were allowed the chance to see it. Still gazing at the stained-glass windows, the huge brass taps and the shining marble pool, she grabbed another towel and dipped it into the water beside Derek. She let the cool water trickle down her face and neck, sighing in relief. After days of being cooped up in the Great Hall with everybody else, it felt good to be clean.

"Chloe?" Derek asked hesitantly as they stood side by side.

"Mm-hmm?"

"About what you said while I was…" He trailed off and wet the cloth again. "While I was Changing. It's not true. You've got a natural gift for necromancy, that's all. You're a necromancer. It's in your blood, like lycanthropy is in mine. That doesn't make you a monster. It just means that you're… different."

Chloe raised her eyebrows. "Are you saying you'd be happy with my power?"

Derek shrugged. "It saved you from the Whomping Willow, didn't it?"

She took a step back. "I don't need a pep talk, Derek. Especially not one that you don't even believe yourself."

"What's that supposed to mean?"

"I saw you tonight. That wasn't a normal werewolf change. Maybe you've managed to convince yourself that you're comfortable with being different, but you had to have been either incredibly self-sacrificing or incredibly stupid to agree to Davidoff's sick experimentation. Which tells me that you don't care much about your own safety. You're not as comfortable with being different as you pretend to be."

He shook his head. "This has nothing to do with me."

"It's got everything to do with you. The first time you spoke to me, you warned me to stay away from Simon if I was going to continue taking potions from Davidoff. Hypocritical, much?"

He glowered. "I'm just trying to figure out Davidoff's game plan so I can help my dad. I didn't know what you knew or what you were. I didn't want you near Simon because I didn't know if I could trust you."

So you do trust me now? she wanted to ask. But something else he'd said stopped her in her tracks.

"Your dad?" she asked, so surprised that she forgot to be angry with him. "What… what does any of this have to do with your dad?"

Derek didn't answer. He just stood there, glowering at her as if hoping that she'd back off if he tried his best to go back to being hostile towards her. But she was done with this game. It was time for her to hear the whole truth. After all they'd been through, she wouldn't accept anything less.

"Derek," she protested, crossing her arms and glaring straight back at him. "This is getting ridiculous. Do you trust me, or not?"

His eyes, which had been narrowed into slits, widened at her words. Then his scowl faded. He pushed his hair back with a long, deep sigh that seemed to be made up of years of worry and anger and frustration. When he spoke now, his voice was still deep, but the gruffness of his tone was gone, replaced by something softer.

"Davidoff's holding something over him. A secret, I guess. Dad won't tell us what – he thinks it's safer that we don't know. Dad's job, our lives… everything's at stake. If we could just find proof of Davidoff's crimes, we'd have something to hold over him. A bunch of kids shouting accusations isn't enough – he practically runs the school, and he's Professor St. Cloud's right-hand man. We need hard evidence."

"I see," said Chloe. She felt hollow. "So you didn't really want to help me at all. You don't really care about what Davidoff's doing. You just want to find something to blackmail him with. You're using me just as he did."

Derek looked horrified. "What? No –"

Chloe couldn't believe she'd been so stupid. "You could have just told me all of this from the start," she said. "At least then I would have known where I stood."

"Chloe," Derek said in a low rumble. "You're missing the point –"

"You approached me because you knew I was one of Davidoff's subjects and you thought I might have a power useful to you. Correct?"

"Well, yeah, but –"

"You tried to threaten me, hoping that I'd be impressed by your act, that I'd realise you would make a better ally than an enemy and see you as someone who could protect me. Then you hoped I'd spill all of Davidoff's secrets and share some vital clue to taking him down –"

"I didn't –"

"And when I refused, you warned me to stay away from Simon, hoping that you could trick me into thinking that Simon was in danger, that Davidoff wanted to hurt him –"

"YES!" Derek roared. Chloe took a step back as he loomed over her, his eyes blazing. "Yes! I admit it, all right? I did all those things. But you…" He trailed off. Both were silent for a moment, breathing heavily as though the heavy words that had come between them were now pressing down on them. When Derek spoke again, he sounded exhausted.

"I was wrong about you," he said. "When you confronted me in the library the next day, I kept my cool, waited for you to confess everything. I thought you'd cracked. But then…" he stared determinedly at the tiled floor and to Chloe's surprise she saw his cheeks flush pink. "As we spoke I realised what you were. A necromancer." Chloe winced. "And I saw that you genuinely had no clue what Davidoff had planned for you, but you weren't afraid. It just made you determined to find answers. Like me."

He looked up at her almost shyly, his eyes vivid in the pre-dawn light. And despite her anger, Chloe felt a stirring ache in her chest. It felt as though every feeling she'd ever felt – excitement and nervousness and longing and fear – had all risen up at once and rolled into a tight ball which now hit her heart like a wrecking ball. She trembled under the new weight, not understanding what it meant or why it had suddenly arrived.

"I'm… sorry," he mumbled so quietly she could hardly hear it. She had a sense that those words were difficult for him to say, that he'd spoken them very few times in his life. The weight in her chest grew heavier.

"Derek," she said cautiously, "I – I know Professor Bae isn't your real father, but I'm sure whatever secret Davidoff's holding over him, he wouldn't want you putting your safety on the line for him."

Derek's jaw clenched. "You sound like Simon," he muttered.

"Well, Simon talks a lot of sense," she countered.

"It was worth it," he said now. "That Change… it was worth any risk."

"Don't say that."

"Chloe," he said, "you know what most werewolves are like. You've seen the pictures in the Daily Prophet."

Chloe had. She shuddered. When she closed her eyes, Fenrir Greyback's deranged eyes stared back at her. She'd never seen him in person, of course. But every witch and wizard had heard of him. He'd been on the front page of the Prophet a few months ago. Just the sight of him had terrified her.

When she opened her eyes, Derek was slumped against the sinks in a rare display of despair. His too-long hair hung lank and limp across his face.

"I just… I don't want to turn into one of them." He turned to look at her, green eyes bright. "You know the worst part of being a werewolf? I have these… instincts. A wolf-like nature. It's not a voice in the back of my head or anything. It's part of who I am. But once the transformation starts, the wolf takes over. I lose myself. Or… the rest of me. Last night…" His eyes gleamed even brighter for a moment as he remembered it. "I was me. The wolf instincts were there too, like they always are. But I didn't lose myself. Davidoff's methods are sick and wrong, but he's done what he promised. He…" Derek paused, before admitting grudgingly, "He's helped me."

Chloe said nothing. She felt almost grateful to Davidoff for his illicit mixture of muggle medicine and magic. Tonight's transformation had been... life-changing for Derek.

Not out of the kindness of his heart, she reminded herself. Davidoff was helping Derek for his own gain, nothing more. He was risking Derek's life even as he helped him.

"Come on," she said, turning away from him. "It's nearly dawn. We'd better get back."

Derek nodded. He threw the towel he was still clutching to the floor, then cleared his throat. "Chloe," he said in a gravelly voice. "I just wanted to say… I mean… well… thanks. For everything."

She stared at him. "Don't mention it," she said, her own voice sticking in her throat like treacle.

He stood there, staring at her for a moment longer. Then he nodded and stepped aside, gesturing for her to lead the way back to the Hall.

X

"So you found him mid-Change?" Simon asked, sounding awe-struck. "And you didn't run screaming in the opposite direction?"

Derek snorted. "No. She stayed so she could yell at me some more." He caught Chloe's eye. "Yelling at me seems to be a hobby of yours."

Simon whistled. "Damn, Saunders. I'm not sure whether that counts as bravery or stupidity."

Chloe laughed. "Probably a bit of both. I wasn't exactly thinking clearly."

They'd met up with Simon as soon as the sun rose, and the three of them were now huddled together by the giant hourglasses which recorded house points. They hadn't bothered with a silencing spell – the Hall was practically empty now. At breakfast, Professor Vasic had announced that the students were free to leave. Liz still hadn't been found, but classes were due to start back up after lunch and everyone was miserable and restless, having spent the entire weekend cooped up together. Now, the grounds were packed, filled with students whooping for joy at their first taste of fresh air in two days. Chloe hoped no one would find the mangled body of the cat she'd raised last night.

Derek had filled Simon in on most of what had happened last night – leaving out Chloe's accidental summoning and the fight they'd had in the bathroom. Simon had listened with awe as Derek recounted his new Change – and when he admitted that Davidoff's experiments were responsible, he'd whacked his brother over the head with surprising force. Clearly, Simon cared about his brother just as much as Derek cared about him. Chloe had kept quiet as the two brothers held the same hushed argument about Derek's safety that she'd had with him only a few hours before. Simon only dropped the subject when Derek agreed – albeit reluctantly – that he wouldn't take any more potions from Davidoff if he didn't know what the consequences would be.

Once Simon's anger had abated though, he seemed disappointed that he'd missed out on the adventure. "Next time," he said, nudging Chloe, "wake me up before you go charging after this oaf, all right?"

"Well, how about tonight?" Chloe said, surprised to hear her voice sound so steady. "I want to break into Davidoff's office."

Both boys stared at her blankly.

"Tonight?" Simon asked. "Why tonight?"

"That's not a good idea, Chloe," Derek said slowly. "His guard will be up now that the school is up-and-running again. And if Liz's disappearance really does have something to do with him, he's had plenty of time in the last few days to dispose of the evidence. It's unlikely that he would have left anything incriminating."

"But that's exactly why we've got to go tonight," Chloe protested. "While there's still a chance, even if it is faint. If we wait a week or two, there won't be anything to find. Plus, you said yourself that these experiments are his life's work. He wouldn't have destroyed them on the off-change that someone searched his office for Liz. If anything, he'd have just moved or hidden them with an enchantment."

Simon nodded. "She's right, Derek. And we can be sneaky. He'll be expecting Dad, or one of the other professors. He won't be expecting three kids. We can use that to our advantage."

Derek looked at Chloe. "You don't have to come with us," he said. "You're not involved."

She stared right back. "Yes, I am."

Simon looked back and forth between them. Chloe waited for Derek to argue, but he surprised her by nodding. "Okay," he said in a soft voice, averting his eyes from hers. "You're in."

Simon raised his eyebrows, but said nothing.

"We'll have to have one person keeping watch while the other two search," Derek said, all business once more. "I think of the three of us, I'm the most qualified for bodyguard duty."

Simon and Chloe nodded in agreement.

"One of you will need to get through whatever enchantments Davidoff's placed on the office." Derek turned to Chloe. "Are you up for that?"

She nodded. "And being half-blood, I have a few other tricks up my sleeve. Like how to pick a lock."

Simon looked surprised and impressed. "You can pick a lock? That is so cool." Derek just gave her a half-smile, like this information didn't surprise him in the slightest.

"And one of us will have to put Davidoff's wards back into place when we leave," Derek continued. "Simon, you should do that. You're good at Charms."

Simon flashed Chloe a sly grin. "Must be all that natural charm I have," he said, nudging her with his elbow. She rolled her eyes and nudged him back, both of them smiling. Derek scowled and waited for them to turn their attention back to him.

"C'mon," he said, climbing to his feet. "If we're going to do this, we need to plan it carefully. Very carefully. Somewhere more private."

"Prefect's bathroom, again?" Chloe asked, but Derek shook his head.

"Everyone's been packed in this hall for days – they're going to want to clean up. Don't worry. I know another place." He led them through the hall. Simon and Chloe followed.

"Knowing Derek," he said, "He'll want a plan so carefully drawn-out that I'll have to storyboard our every move."

Chloe laughed. "Like muggles do for movies!"

"Right," Simon said with a grin. "What do you say, movie girl? Want to help me choreograph tonight's scene? You know, it would make an awesome radio show, too." He cleared his throat and put on an exaggerated stage-whisper, like the voices of the radio hosts Chloe had heard on the Wizarding Wireless Network. "Tune in weekly for the misadventures of three young Hogwarts students as they face horrors unknown in the attempt to take down their evil professor and foil his wicked plans once and for all!"

Chloe laughed and even Derek cracked a smile. And so caught up were they in Simon's exaggerated impressions, that not one among them saw the dark-haired girl hovering at the bottom of the staircase and watching their ascent with a sly smile on her face.

A/N: I apologise for the long delay in getting this chapter out. There are only three more chapters until the end, and I promise that I haven't lost my motivation to continue! Thank you to everyone who has stuck with this story so far. Your comments and reviews mean the world to me.

So, who was the dark-haired girl watching them? Tori? Or Rae? Feel free to leave your theories! :)