The Astronomy Tower.

Harry Potter stumbled as he and the headmaster of Hogwarts, Albus Dumbledore, landed heavily in the back yard of the wizarding pub The Three Broomsticks in Hogsmeade. However, Harry quickly righted himself and grabbed onto Dumbledore, who was barely able to stand. The pair had been on a mission to track down one of Voldemort's Horcruxes, but the evening had gone all wrong when Dumbledore had been forced to drink a poisoned potion in order to get to the Horcrux. Now the headmaster was seriously ill, and Harry needed to get him back to Hogwarts as quickly as he could.

"Hold on Sir, we're almost there," Harry muttered to Dumbledore, even though the castle was a good fifteen minute walk from the village. However, thanks to the anti-apparition charms around the school they hadn't been able to get straight onto the grounds, even if in Harry's opinion they could have gotten closer than the village.

"Albus!" a worried feminine voice called and Harry turned his head to see the landlady Madam Rosmerta hurrying out of the back door of the pub, wrapping a robe around herself. "What happened?" she asked, pausing slightly when she noticed that Dumbledore looked rather the worse for wear.

"It's a long story," Harry replied. "We need to get up to the castle, and quickly."

"I'm not sure help is what you'll get up at the castle," Rosmerta remarked.

Wondering what she meant, Harry turned his head towards the castle and gasped in shock at what he saw. Hanging ominously above Hogwarts was the horrifying sight of The Dark Mark, which was usually cast to signify the Death Eaters had attacked and someone had lost their life.

"No," Harry gasped, turning towards Dumbledore to find the headmaster was also staring up at the school in horror.

"We need to get up there now," Dumbledore rasped. "Rosmerta, may we borrow a couple of broomsticks?"

"Are you in any state to fly?" Rosmerta asked in concern.

"I'll manage," Dumbledore replied, seeming to find some strength from somewhere at the prospect of his school been in danger.

"I'll find you a pair," Rosmerta said as she hurried back inside.

"What do you think is going on?" Harry asked, hoping that his friends were okay.

Before he'd left that evening, Harry had enlisted his two best friends, Ron Weasley and Hermione Granger, to patrol the castle with other members of the old DA and watch out for trouble. And of course Harry knew that before he and Dumbledore had left, the headmaster had ensured that a small section of the Order of the Phoenix were at the castle. Looking back, it was as thought they'd both expected trouble once they'd left the castle.

"I don't know, but let's hope we can get back in time to stop it getting worse," Dumbledore replied.

"Can it get worse?" Harry asked, once again gazing up at the Dark Mark hovering in the sky. "Doesn't the mark mean someone is already dead?"

"I have known the mark be used as a warning that death is approaching," Dumbledore answered. "But either way, we need to get back to the castle as quickly as we can."

Fortunately Rosmerta didn't take long to return with the two broomsticks. And once Harry and Rosmerta had helped Dumbledore onto his broomstick, he and Harry rose into the air and set off towards the castle. Speed wise Harry could have reached the castle a lot faster than Dumbledore, but he kept pace with the headmaster, making sure that the old wizard didn't tumble from his broom and down to the ground below.

After what seemed like a slow ride, but in reality was less than five minutes, the pair came to land atop of the astronomy tower. Propping their brooms against the wall, Harry checked Dumbledore was managing. Fortunately the adrenalin seemed to be keeping the headmaster going and while he still looked weak and fragile, there was a determination in him that Harry knew would prevent him from collapsing before they dealt with the problem at hand.

"I'm fine Harry," Dumbledore replied. "Let's get going."

Harry hurried over to the door to the astronomy tower, but when he pulled it open he paused as he heard distant footsteps from below.

"Someone's coming," he hissed to Dumbledore.

"In that case, get back," Dumbledore ordered. Pulling Harry against the wall, the headmaster whipped out his wand and froze Harry to the spot.

"What are you doing?" Harry demanded, taking totally surprise by Dumbledore's actions.

"It's for your own safety Harry," Dumbledore replied, quickly silencing Harry and casting a disillusionment charm on him before he could protest further.

Stuck in the corner of the Astronomy Tower, frozen, silenced and invisible, Harry silently fumed at the headmaster. There was no way of knowing who was heading up to the tower, and if it was an enemy, Dumbledore was in no position to defend himself. Even though he had his wand in his hand, Harry could see how exhausted he was, and he wouldn't stand a chance against a dangerous opponent. And here was Harry, young and fit, and stuck unable to help the headmaster.

Harry still hadn't managed to break out of Dumbledore's spells when the door to the Astronomy Tower opened all the way and a figure emerged from the dark stairwell. As the figure stepped into the moonlight, Harry would have growled angrily if he could as he recognised the pale figure of Draco Malfoy. All year Harry had been convinced that Draco was a Death Eater and up to no good, but just recently he'd begun to wonder if there wasn't more going on with the Slytherin that he'd initially thought.

"Draco," Dumbledore said as the teenager advanced on the headmaster, his wand in his slightly shaking hand.

"Headmaster," Draco replied in a voice little more than a whisper.

"You don't have to do this, Draco," Dumbledore said, holding out his hand towards the Slytherin. "I know you don't want to do this."

"You know nothing," Draco spat.

"I know this isn't what you want," Dumbledore retorted. "I know you're being forced into doing this. I know the hold he has on you."

"How?" Draco asked with narrowed eyes, raising his wand and aiming it at the headmaster.

"I know of the promise your mother asked Severus to make," Dumbledore said.

Harry recalled an overheard conversation earlier in the year, when Draco had mentioned an unbreakable vow to the Potions Professor, Severus Snape. At the time he hadn't learnt any more, but it would seem as though Draco's mother, Narcissa, had been the one to initiate the promise.

"Severus," Draco spat with a disappointed shake of his head. "I should have known he would have told you."

"He didn't betray you, Draco," Dumbledore urged. "He was trying to protect you. He told me what you have to do."

"Did he now?" Draco asked with a bark of laughter. "And did he tell you that he promised my mother that he will do it for me if I can't do it?"

"I'm aware of that," Dumbledore replied with a nod. "But you don't need to worry about any of that Draco. Let me help you. I can help you, I can save you. Just trust me, Draco."

As Dumbledore took a step towards Draco, his hand held out in a consolatory fashion, a low clap sounded from the shadows. Harry hadn't noticed anyone else enter the Astronomy Tower, but now he could see a shadowy figure lurking in the doorway. Still clapping slowly the figure stepped forward into the moonlight and if he hadn't been frozen, Harry would have fallen down in shock as his best friend, Hermione, put in an appearance.

"That is a very impressive act. I would almost be convinced if I didn't know everything you're saying is just a pile of lies," Hermione drawled.

"Miss Granger?" Dumbledore queried, clearly as confused as Harry by Hermione's presence.

"Headmaster," Hermione returned with a slight nod. "Although I do think it's time to clarify something. It's not Miss Granger, it's Miss Riddle. Granger is my mother's maiden name."

"Riddle," Dumbledore stammered, taking an uncertain step backwards.

"Yes Riddle," Hermione retorted with a roll of her eyes. "Don't act dumb, I'm sure you've worked out who my father is. And while we're clearing things up, you can drop your cloaking spell on Harry. I know he's up here somewhere."

Looking at Hermione as though she was a stranger, which to be fair she was as the girl they'd known had clearly been a lie, Dumbledore waved his wand to drop the disillusionment charm on Harry.

"Hello there Harry," Hermione purred, flashing her friend a dangerous smile.

"Hermione," Harry spluttered, finding that Dumbledore has also lifted the spell keeping him quiet, although he was still frozen in place. "I don't understand."

"Surprise, surprise, Potter's too thick to see what's right in front of him," Draco sneered, and when Harry glanced towards the blond he saw that his nerves seemed to have vanished and he was his usual smug self. "Let's spell this out for you Potter. Hermione is the daughter of The Dark Lord. She's your enemy."

"No," Harry said, refusing to believe it. "Hermione's my friend. She's the sister I never had."

"Yet you've cast me aside time and time again in favour of Ron," Hermione pointed out. "Not that it would have mattered," she added with a shrug. "You've been my enemy since the day you destroyed my father. Because of you, I didn't have my father growing up."

"Because of your father, I didn't have either of my parents," Harry argued. "But I don't blame you for that. You can't help who your parents are Hermione."

"That's rich coming from you," Draco cackled. "You and Weasley have judged me based on my parents from first year."

"And we were right," Harry sneered. "Look at you now. Working with the Dark Lord's daughter."

"Not just her, there's dozens more Death Eaters in the castle," Draco replied. "Including Severus by the way," he added to Dumbledore.

"You're being used Draco," Dumbledore pleaded with the blond. "Don't forget I know everything."

"You know what we wanted you to know," Hermione snorted. "We engineered the entire thing with Draco. He was never forced to take the mark. Hell, he doesn't even have the mark."

"Not yet anyway," Draco said as she pushed back his left sleeve to show his bare forearm.

"That'll be your reward for helping me," Hermione said, flashing Draco a smile.

"But Severus, and the unbreakable vow," Dumbledore stammered, clearly having a hard time taking in the deception.

"All an act," Draco crowed in triumph. "Mother and Severus acted out their part so that you would believe him. I then made sure to act as though I was being forced into serving The Dark Lord. Hell, I even got that insufferable ghost Myrtle feeling sorry for me. And of course I allowed Potter to see me struggling."

"No, it can't have been an act," Dumbledore gasped, still struggling to accept what was right in front of his eyes.

"It was," Hermione confirmed. "And you might have been able to work that out earlier if your offer to help Draco was genuine. If you'd really wanted to help Draco, you would have done so much earlier. But you never wanted to help him, did you Sir? He couldn't do anything for you, could he, so what use would it have been trying to help him? Not like Harry. Now he can win a war for you, so you have to suck up to him. Not that you did a good job of helping him though. But Harry is too blind to realise that you're the reason he grew up with his aunt and uncle. He's too enamoured with you to see that if you'd wanted to, you could have saved him from his miserable life. But you didn't care, did you? Harry was no good to you at such a young age. But now he can be your hero, you're all over him."

"That's not true," Dumbledore said, turning to Harry with pleading eyes.

"I don't believe her," Harry assured the headmaster as he glared at Hermione. "I can see now she's nothing but a monster. She's been helping Malfoy this last year."

"We were working together," Draco confirmed.

"On everything?" Harry asked. "Even the cursed necklace and the positioned mead? They hurt innocent people, Hermione."

"Collateral damage," Hermione retorted with a shrug. "Besides, Katie was never in any serious danger from the necklace, it was only a mild curse."

"And what about Ron?" Harry snarled. "He could have died."

"And that would have been brilliant," Hermione cackled. "You know Harry, I hate you because I was raised to hate you, and because I know you're going to do everything you can to destroy my father. If things were different, I'm not sure I would hate you. But Ron, he's a different matter. I hate Ron because he's an odious person. He's turned on me so many times I've lost count. He's even turned on you, but yet you forgave him with barely more than a shrug. You won't be able to count on him when it really matters, Harry. When it comes down to it, the only person Ron truly cares about is himself. He's a selfish, bitter boy, and the worst thing you ever did was save his life. You should have let him go, Harry."

"Ron is worth ten of you," Harry yelled, tears rolling down his face as he accepted that he'd well and truly lost Hermione.

"Hermione, we need to get going," Draco hissed as he checked his watch.

"You're right, I'm bored of this now," Hermione said as she turned away from a crying Harry. "You know headmaster, Draco was never going to be the one to kill you. That pleasure was always going to be mine."

"Murder is harder than you think, Hermione," Dumbledore said, standing firm in front of the young girl who had so surprised him by revealing her heritage.

"What makes you think you're my first victim?" Hermione questioned with a smirk as she raised her wand and pointed it squarely at Dumbledore's chest. "I know what I have to do, and I'm ready for it. Goodbye, Sir. Avada Kedavra!"

Harry registered the shock on Dumbledore's face as the jet of green light flew from Hermione's wand and struck him square in the chest. Dumbledore was so surprised by the fact Hermione had cast the killing curse that he stumbled backwards and Harry let out a horrified cry as he tumbled over the low railing and disappeared from view. For several moments, time seemed frozen and Harry could do nothing but watch as Dumbledore vanished from sight and Hermione and Draco shared smug smirks, complete with evil laughter. And then everything snapped back into focus and Harry felt the remaining spell of Dumbledore's break. Rushing forward, he leant over the railing and wailed at the sight of Dumbledore lying sprawled on the grass below.

"Murderer!" he cried, whirling back around to confront Hermione, only to find no sign of her and Draco.

Hearing their feet running down the stairs, and their laughter floating tauntingly back up to him, Harry sprinted after the pair. He wasn't able to catch them on the stairs, and he was momentarily distracted when he almost tripped over a prone body at the foot of the stairs. However, he didn't take the time to dwell on who'd he'd almost fallen over, and if they were dead or not. His focus was on Hermione and Draco, and even though he wasn't sure which direction they'd gone in, he used his instincts and headed down the castle, favouring the front exit.

Bursting out of the front doors, Harry saw several figures sprinting away from the castle. Draco stood out the most with his platinum blond hair, but Harry could also make out the dark figure of Severus Snape. And of course after years of knowing her, there was no mistaking Hermione, who was running alongside Draco.

"Bitch," he bellowed, shooting a curse at Hermione which missed her by inches.

"Thanks for noticing Harry," Hermione cackled as she turned around to face Harry again. "It's good to finally be free. No more good girl, Hermione. Now I can be the bad girl I was raised to be."

Blowing Harry a taunting kiss, Hermione blasted him off his feet before turning and carrying on her exit plan. By the time Harry got to his feet, the group were almost at the gates, which signified the end of the boundary line. Chasing after them, Harry watched as the Death Eaters left school premises and vanished into the night air. Snape and Draco were the two who vanished before Hermione, but when she reached the boundary, she turned again and grinned at Harry.

"See you soon, Potter," she cried with glee before she also vanished into the night air and Harry was left alone, feeling devastated and broken.

Falling to his knees in a sob, Harry stared at the spot where he'd last seen Hermione for nearly five minutes. Still hardly able to believe what he'd just experienced, he then slowly got back to his feet and turned to head back to the castle. Now he had to face Ron and his other friends, and explain that not only was Dumbledore dead, but that Hermione had killed him and she was now their enemy. But how was he going to explain that the girl they'd all loved and trusted had been using them all along, and she'd always been the daughter of their most deadliest enemy?

Not sure of what lay ahead, Harry vowed that no matter what he wasn't going to let Hermione get the last laugh. She may have triumphed this evening, but now she'd lost the element of surprise. Next time she struck, Harry would be ready for her, and he wouldn't rest until she and her father had been defeated. But what he didn't realise was that Hermione would not be beaten easily and as he vowing his revenge on her, she was plotting his demise and rise of The Dark Lord, with her at his side as his daughter and heir.