Both Katie and Professor McGonagall we're completely silent as they walked along the corridor to the office. Katie's mind was working furiously. McGonagall wanted to tell her the truth? But did she not already know the truth? She was a Horcrux, part of Voldemort's soul was encased inside her. That was why she was a Parselmouth and that was why Voldemort had been trying to persuade her to join him. Perhaps McGonagall was going to explain how she had come to be a Horcrux in the first place.

Professor McGonagall's office was quite warm so Katie slipped off her cloak, draped it over the back of her seat, straightened the cuffs on her now visible jumper, and seated herself. For at least half a minute, McGonagall did not speak. Her strained face was expressing the same amount of hesitance that Harry's, too, had shown.

"I've been speaking with Professor Dumbledore," McGonagall began at last, and Katie took note of how her voice quavered ever-so-slightly. "He's informed me about... Voldemort and his Horcruxes."

McGonagall shivered, but whether it was because of the mention of Voldemort or Horcruxes, Katie did not know, nor did she ask.

Taking a deep, slightly shaky breath, McGonagall went on. "He told me that Mr Potter..." she paused, "that Mr Potter believes that you are a Horcrux."

Katie's blood ran cold. She wasn't sure why she was so surprised to hear this. She had, after all, anticipated that this was what the Professor would want to discuss with her. Still, Katie said nothing, instead choosing to stare at the desk in front of her.

"This is not true." McGonagall said simply.

At once, Katie tore her eyes away from the table and focused them avidly on Professor McGonagall, whose jaw was clenched as though trying to refrain her from saying something.

"I'm not — I'm not a Horcrux?" Katie asked, half disbelieving, half hopeful.

McGonagall nodded slowly. "You are not a Horcrux."

"But then..." Katie's mind was pulsing with a million questions, as it so often was. "Why can I talk to snakes? Why am I an Occlumens? Why does Voldemort want me? And why would Dumbledore say that I was a Horcrux if I'm not?"

But McGonagall was shaking her head. "Professor Dumbledore did not say that you are a Horcrux. If I recall correctly, his exact wording was that a piece of Voldemort lives inside you."

"But was he not referring to Horcruxes?" Katie asked. She was feeling very bemused now. "What else could that mean?"

McGonagall shut her eyes, kept them close for a few seconds, then heaved yet another deep breath.

"Voldemort wants you on his side," Professor McGonagall said slowly, "because of who your father is."

Katie blinked slowly at her teacher. "So you know?" she questioned. "You know who my father is?"

"I do," McGonagall bowed her head, an utmost apologetic look painted on her lined face. "Professor Snape told me some time ago."

"Professor Snape?" Katie repeated quickly. "Snape knows who my father is?"

McGonagall arched an eyebrow. "You know, of course, that Professor Snape was once a Death Eater, and a very trusted one at that. He has a lot of inside information on Voldemort and his ranks."

"So my father is a Death Eater?" Katie put the pieces of the puzzle together. She supposed that made sense — her mother was a Death Eater, after all.

Professor McGonagall stared dejectedly at the Slytherin girl in front of her for many still moments.

"Professor Dumbledore wishes me not to tell you this," she said slowly, thinking hard on each word and every syllable. "But after I found out that you tried to... that you tried to... use the Killing Curse on yourself, I decided that it was dangerous to keep the truth from you any longer."

Katie looked down at the stone floor, which she was absently kicking.

"I warn you, this might come as a bit of a shock," McGonagall said quietly, yet Katie still did not meet her eyes. "Your father is—"

There was a loud crash from outside in the corridor. Both Katie and McGonagall startled, and Katie actually swore rather loudly, but either the teacher didn't hear or she simply did not care. Professor McGonagall was already on her feet and sweeping towards the door.

"PEEVES!" she roared.

McGonagall left the office, slamming the door shut behind her. Katie contemplated for many moments whether or not she should just stay put and wait for McGonagall to return, but curiosity got the better of her and she, too, left the office. Glancing up and down the corridor, Katie found that Professor McGonagall was no where to be seen, but there was a fallen suit of armour laying in pieces on the floor, which explained the deafening crash.

"MURDER! MURDER IN THE BATHROOM! MURDER!"

Rapidly growing cold, Katie wheeled around. Staring down the hallway, she saw that the door to a nearby boy's bathroom was ajar, and someone, a girl, was wailing and screaming from within. Without thinking twice, Katie dashed towards the open door and ran inside the boy's bathroom, stopping dead at the sight that lay in front of her.

Moaning Myrtle was bobbing overhead, squealing and crying. A cistern had been smashed and water was pooling across the floor. With a horrible drop of her stomach, Katie saw that fresh streams of blood were rippling through the water. Draco was lying in a pool of his own blood and Harry was on his knees at his side, muttering in a panicked way to himself.

Slipping and staggering, Katie splashed forwards. Harry looked up, terrified, at the sound of someone splashing towards him. He opened his mouth to speak but no words came out. Like Harry had done, Katie dropped to her knees beside Draco. His face and chest were slashed open as though with a sword, and for a second Katie thought he was dead until he stirred and let out a small whimper.

"What did you do?" Katie shouted at Harry.

Harry said nothing.

"WHAT DID YOU DO?"

Harry was apparently too stupefied to speak. Katie aimlessly put her hands on Draco's stomach; the excessive amounts of blood pumping from his face and chest was making her feel sick and dizzy, but she had to do something, she had to help. Only one idea came to mind. She tore off her jumper and pressed it firmly against the wounds on Draco's chest as an effort to stop the bleeding, but, with a stab of horror, she saw the blood soak right through her jumper and she let out a sob.

"What spell did you use?" she demanded. Draco was paling underneath the river of scarlet that was obscuring his face. Harry shook his head frantically.

The door banged open. Professor Snape entered the bathroom, looking livid, and Katie felt a great sense of relief crash down upon her.

"Professor—" she croaked out.

Pushing Harry aside, Snape crouched down beside Draco and waved his wand over him, muttering in incantation that almost sounded like a song. Katie watched, heart beating wildly, and the blood flow seemed to ease. With a second murmur of the incantation, Draco's wounds stitched themselves, and Snape helped the trembling boy to his feet.

"He needs the hospital wing," Snape told Katie. "There may be a certain amount of scarring, but if he takes dittany immediately we might avoid even that."

Katie didn't need to be told twice. Draping Draco's arm around her shoulder and wrapping her own around his waist, she led him, slipping slightly, from the bathroom. He was still shaking and letting out occasional choked sobs.

"What spell did he use?" Katie asked in a much softer tone than the one she had spoken to Harry with.

"I — I don't know." Draco's voice shook just as much as his body.

"It's all right," Katie told him gently. "You'll be fine, I've got you..."

When the two Slytherins arrived in the hospital wing, each of them soaked to their skin and drenched in blood, Madam Pomfrey let out a horrified yelp. She lay Draco down on a bed and Katie told her that Professor Snape had recommended dittany, which Madam Pomfrey gave him. After advising Katie not to stay long because Draco needed some rest, Madam Pomfrey allowed Katie to clean the dried blood from his face and retreated to her office. There was nobody else in the hospital wing.

Katerina dabbed the cloth soaked in warm water on Draco's face and he hissed in pain. She gave him a weak smile.

"I'm sorry," she muttered. "I know it stings."

Draco shook his head. "It's fine."

"What happened?" Katie asked. Now that the initial shock had worn off and she had been assured that Draco was going to be all right, she was very curious as to why Harry had cursed Draco, but before Draco could respond, the door opened and the defendant in question entered. Katie got to her feet at once.

"Get out," she said coldly. Harry opened his mouth to speak but Katie wasn't going to let him get the chance. "I mean it, Harry. Leave before I make you leave."

Still, however, Harry stepped further into the room. Katie reached for her wand but realised that she had left it inside her cloak, which was still on the chair in Professor McGonagall's office.

"What spell did you use?" Katie demanded of Harry once more.

A look of extreme guilt shadowed Harry's countenance.

"It was one from the Half-Blood Prince's book..." he said quietly.

Katie stared at him, completely thunderstruck. "And did you know what it does before you used it?"

"No," Harry replied quickly. "No, of course not! But it was labelled 'For enemies'."

Katie let out a shout of shrill laughter. "Enemies?" she said mockingly, in a cold, high-pitched voice that was so unlike her own. "Oh, so Draco's your enemy now, is he?"

"Well — yeah..." Harry responded, looking bewildered. Katie scowled at him.

"Voldemort is your enemy, Harry," she said. "You and Draco have a petty school rivalry which, quite frankly, I think you should both drop. It's childish and it's getting ridiculous, especially if you've resorted to using lethal curses—"

"I didn't know what it did!"

"That's the whole point!" Katie yelled, walking dauntingly towards the Gryffindor. "You used an unknown, non-Ministry-approved spell on someone, Harry. The fact that you didn't know what it does makes it worse! It could have killed him!"

"Will you stop yelling at me!" Harry snapped. "Snape's already done enough of that!"

"Oh, I wonder why!" Katie shouted sarcastically, flailing her arms around.

The door to Madam Pomfrey's office opened and she emerged looking almost as furious as Snape had been when he found Draco bleeding out on the bathroom floor.

"Get out, Mr Potter!" she shrieked, hurrying towards him. "Causing such a scene — out, out!"

Harry did not need to be told twice. Without so much as glancing at Katie, he turned on his heel and rushed from the hospital wing. Once the door shut and Madam Pomfrey returned to her office once more, Katie threw herself down on the edge of Draco's bed and placed her head in her hands.

Everything with her and Harry was getting out of hand. It was an endless cycle of recurring events: once day, they would be totally fine with each other — best friends, each seeking comfort from the other, and the next day they were at each other's throats. It had been like this ever since they split in the early months of their fifth year, and never in her life had Katie regretted kissing him before the First Task more than she did in that moment.

"Are you OK?" Draco asked warily. He took note of the fact that she was crying but chose not to mention it — she was putting in a great deal of effort to hide it from him.

"I'm fine," Katie said shakily. "I just... can't deal with him anymore."

"Who are you telling?" Draco chortled. "He's been getting under my skin since first year."

Katie let out a weak laugh, followed by a heaving sigh. She then shook her head.

"Why are you asking me if I'm OK?" she said. "You're the one whose just had your chest split open."

"Don't suppose I'll be playing the match against Ravenclaw next week, then?" he smiled.

Katie chuckled. "Definitely not."

***

Harry was given detention with Snape every Saturday until the end of term, which Katie actually thought was quite a fair punishment. However, she did think it was a bit harsh that he was being forced to miss Gryffindor's last Quidditch game of the year because he would be serving detention.

Despite Harry's absence, Gryffindor beat Ravenclaw, meaning that they won the Quidditch Cup, and Katie could not find it in herself to be disappointed. After their loss against Hufflepuff, she knew that Slytherin had no chance of winning, so she was glad that Ron and Ginny got to experience the euphoria of winning the Cup for the first time. As well as this, rumours spread that, during the after-party in the Gryffindor common room, Harry had kissed Ginny. These rumours were confirmed the next day when Harry and Ginny could be seen walking together in the halls.

Katie, who had been walking hand-in-hand with a newly discharged Draco Malfoy, caught Harry's eye, glimpsed Ginny, and smiled. She recalled that Ginny had fancied Harry from the very first time she met him, so it was sweet to see that they were finally together.

As term was slowly but surely drawing to a close, Katie observed that Draco was getting more clingy than usual. She supposed it was because he knew that in a few weeks time they would be departing for two months, but he also seemed to be on edge, casting nervous glances over his shoulders as though expecting someone to attack him from behind, and disappearing without a trace for hours, claiming that he had just been in the library.

One afternoon, Katie had just sat down in the Great Hall with Pansy for lunch when someone tapped her on the shoulder. She craned her neck around and smiled when she saw that it was Draco.

"Want to come have lunch by the Lake?" he asked.

Katie looked up at the ceiling. The blue of the sky was completely shielded by thick, grey clouds. Katie raised an eyebrow.

"Not exactly perfect weather for a picnic, is it?" she said.

Draco chewed his lip anxiously. "Please?" he added quietly.

Katie looked to Pansy, who merely shrugged before turning away and engaging in conversation with Millicent Bulstrode. Katie thought, why not, and followed Draco from the Hall and into the vaguely dull grounds. By the time Katie and Draco reached the shore of the Lake, the clouds had parted and the sun was splitting the sky.

"So," Draco began, sitting himself down on the grass, "Potter and the Weaslette. Didn't see that one coming."

He was eyeing Katie scrutinisingly and she could tell that he was tracing her features for any hints of jealousy. Katie shrugged nonchalantly and bit into her sandwich.

"Honestly, I'm not surprised at all," she said casually. Draco raised his eyebrows. "I mean, she's liked him forever, it was only a matter of time before they started going out, really."

For a few, short moments, Draco pondered over this statement.

"So... so you don't care at all?" he questioned slowly. Katie rolled her eyes and grinned at him.

"Jealous, are we?" she teased.

"No, no," Draco said hastily, though his face was turning pink. "I was just wondering..."

Katie hummed, though she still smirked at him for a few seconds, before going back to her sandwich and gazing out at the wondrous Lake. It was hard to believe that she only had one year left at Hogwarts. Sure, she did not have quite the emotional attachment to the place that Harry had — it was, after all, simply just school to her, while for Harry it had been the first home he had ever known, but she would still be sad to say goodbye to it.

"By the way," Katie piped up after a few minutes of peaceful silence, "I want my Shakespeare book back."

If Draco hadn't been blushing before, he certainly was now.

"I haven't taken your Shakespeare book!"

"Oh really?"

"Really!"

Katie's eyes flicked down to Draco's bag, which lay open on the grass beside him. The rim of a leather-bound book was poking out of the top.

"Then what's that?" she nodded towards the book.

Draco snapped his head around, turned an even deeper red, and kicked the book further into his bag. Katerina laughed.

"Draco Malfoy likes Muggle poetry," she said slowly, savouring every word as Draco glared at her. "Who would've thought?"

That evening, Draco asked Katie to help him study, which she found rather odd because he achieved better marks than her in almost all of their classes, but she agreed nonetheless. However, after about a half an hour, they found that the common room was much too bustling and noisy and not a suitable environment for studying. There was no point in going to the library — it would be closing soon, so, after checking that Blaise, Theodore, Crabbe and Goyle were all in the common room, they slipped upstairs to the boy's dormitory and settled on Draco's bed, where they pored over their Alchemy books.

"I don't get it." Draco threw his quill down.

Katie quirked an eyebrow. "You don't understand the transmutation of graphite into gold?"

"Not one bit."

"Draco, it was the first thing we learned this term."

"Yeah, well, I forgot."

Katie glanced down at her watch and saw (and she let out a tiny gasp) that it was awfully late. In fact, it was a miracle that none of the other sixth year boys had come up to bed yet, but, it was a Friday and there were no classes to be up early for in the morning, Katie supposed. Still, it was getting late, and Katie could feel tiredness washing over her. She began packing away her books as Draco watched with a certain confusion in his eyes.

"Where are you going?" he asked.

"Bed," she replied simply. "It's getting late and I'm a little tired. I'll see you in the morning."

She kissed him swiftly and was already on her way to the door when his hand clasped around her wrist. Looking back, she saw that he was refusing to meet her gaze, but his eyes were slowly filling with tears.

"Don't go." he said quietly.

Katie blinked at him slowly, expecting him to say more, but when he didn't she smiled nervously.

"Draco... I have to go. I can't stay here." she laughed gently while glancing down at his hand, which was still clinging rather loosely to her wrist."

"Is everything all right?" she asked worriedly when Draco remained quiet. He cringed as though he had just had a horrible thought or was refraining from saying something. It proved to be the latter, because his next word was spoken in a voice that was barely louder than a whisper.

"Stay."

Katie's eyes danced between the door and the boy who still kept his eyes firmly fixed anywhere but on her. For some inexplicable reason, she felt a sudden surge of pity course through her. Maybe Draco was just feeling particularly upset about his father being in Azkaban? Or perhaps he was still reliving the trauma of what had happened between him and Harry and would prefer not to be alone. That would explain why he wanted to be around Katerina more often than usual.

"Yeah, all right," she agreed. "I'll stay."