Yes, sorry this took so long. I have a number of one-shots for other fandoms almost done, and…well…I re-installed Age of Wonders, which ate a couple of weeks of spare time. Bad Brownish, bad. Next update should take less than three months.

*

Dumbledore tossed a handful of Floo powder into the fire burning in his office's fireplace, said "Number Twelve Grimmauld Place!" in his dry tenor, and vanished in a puff of green flame. Harry took a handful of powder from the pot Dumbledore had showed him, and stared into the fire for a moment. He threw the powder in, stepped over the edge of the fireplace, and called out his destination. The usual terrifying whirl of colour and sensation, and then he was stepping out from the hearth in Number Twelve's living room. Dumbledore was to the right, standing in the corridor and frowning in the direction of the stairs. Harry could hear someone clattering down the stairs, the only noise in the house.

"Dumbledore!" A female voice called, and Harry trembled in remembered anger. His hands curled into fists. "Dumbledore," Bellatrix said again, from the sound of it standing at the end of the corridor. "That poisonous little elf refuses to cook anything other than mushroom soup! Tell it to—"

"Be silent, Bella," Dumbledore said. "Come into the parlour." Dumbledore stepped back through the doorway and stood next to Harry, although Harry wasn't sure which person Dumbledore was guarding. Bellatrix swept into the parlour indignantly, and stopped at the sight of Harry, who was glaring at her. He had promised Dumbledore, he told himself. But seeing her here, in Sirius's house…she was mocking Sirius. He ached to pull out his wand. Bellatrix opened her mouth, but could not make a sound. She glared at Dumbledore murderously, and made a show of gesturing at Harry, then around at the house, and then at herself.

"The protections around Harry's residence have failed," Dumbledore said briskly. "He will be staying here until the beginning of the Hogwarts term. You are not to assault him, physically or magically."

Bellatrix scowled, waved at herself, and gestured at Harry pointedly.

"Harry has given me his word that he will not harm you," Dumbledore said. "Though I would caution you not to test him. I trust Harry's sense of responsibility, but he is only human." Dumbledore turned to Harry, put a hand on his shoulder. "Your things are in the first bedroom on the second floor. If you grow weary of schoolwork, there is a fairly comprehensive library on the third floor. I believe Remus has removed all the cursed tomes." Dumbledore leaned in a little closer to Harry, and lowered his voice. "I am truly sorry to put you in this position, Harry."

"I'll survive, Professor," Harry said, as calmly as he could. Bellatrix was glancing between Harry and Dumbledore with interest.

"Ah, Harry," Dumbledore breathed. "There is more than one kind of danger. But you have always risen to the task at hand," he went on, sounding distant and faintly sad.

"Professor?" Harry said. "Are you all right?"

"Merely absorbed in my own follies, Harry," Dumbledore said. He glanced at Bellatrix. "Sirius's will deeded this property to Harry. If you have any concerns regarding house-elf management, you should address them to him." Dumbledore strode to the hearth and reached for Floo powder, but Bellatrix thumped the wall and gestured to her mouth. "Ah. You may speak, Bellatrix," Dumbledore said. A moment later, he vanished in a whirl of green flame. Harry and Bellatrix stared at each other for a long moment. Keeping his face blank, Harry walked past her to the corridor. When he glanced back over his shoulder, Bellatrix was smirking, watching him carefully. He resisted the urge to wipe the amusement off her face, and went on up the corridor.

The next morning, Harry was laying on his bed, staring at the ceiling, when someone knocked at his door. It took him a moment to remember that there was only one other person in the house, and he felt the flush of anger again. Well, perhaps it was Dumbledore, checking that Bellatrix hadn't killed him, or vice versa.

"Come in," he called. The door was flung open, and Bellatrix leaned against the doorframe. She was bone-pale, with striking features, and she reminded him vividly of Sirius, when Harry had first met him that night in the Shrieking Shack. Perhaps it was the slightly threadbare robes, or the air of arrogant madness.

"Speak to the elf, Potter," she said sharply. "Unless you want to eat boiled fungus for the rest of your incarceration."

"Go away," Harry said, trying for calmness but sounding choked instead. Bellatrix snorted.

"Gladly. Just as soon as you give the horrible thing its orders."

"Go away," Harry repeated, rolling over to face away from Bellatrix. It made his back itch, but Dumbledore had assured him that Bellatrix would not be able to attack him. "Or I'll tell Kreacher to serve you dog food."

"Why did you ask me in, then?" Bellatrix snarled.

"Thought you were Dumbledore," Harry mumbled, then shook his head. He didn't have to explain himself to this hag. He rolled over again to face her, and picked up his wand from the bedside table. "Bugger off, Lestrange," he said, using the straightforward vulgarity to centre himself. He hated her, and didn't owe her a thing, he reminded himself.

"It's Black," she said stiffly. "Failure to come to the defence of your spouse negates the marriage."

"Oh, you had a falling out with your husband," Harry said lightly. "Pity, that. You had so much in common. Both mad, both murderers, both pieces of trash who shouldn't have a wand--" Bellatrix bared her teeth and reached for her wand, and Harry hit her with a blasting hex on reflex.

She was tossed backwards out of the doorway and slammed against the wall. Harry felt a fierce satisfaction, replaced quickly by guilt. The Ministry might not be able to detect underage magic through a Fidelius, but he had promised Dumbledore he wouldn't harm Bellatrix. She probably wasn't going to be a useful source for the Order if she was concussed all the time. He watched her push herself to her feet.

"Angry, Potter?" she drawled, wand at the ready. "Whatever did I do to you?" Harry growled. How dare she – he was only vaguely aware of getting to his feet, preoccupied with pouring his rage into another blasting hex. Bellatrix flicked her wand in a spiral, and a swirling blue shield appeared, fracturing and absorbing Harry's hex. Bellatrix made as if to cast, but instead her entire body went rigid for a moment. "Blasted old fool," she growled. "Does hurting those who can't fight back make you feel good, Potter? Powerful?" Harry threw out another hex, which Bellatrix knocked away with a flash of silver light. The deflected hex struck something out in the corridor with a loud whoom.

"Get out of my sight," he said tightly.

"Or you'll curse me, I suppose," Bellatrix said, and sighed. Harry tossed an exploding curse at her feet, but she flicked her wand in a strange triangular motion and the curse fell apart before striking the floor. "I can't attack you, Potter, but you can't best me." She tapped her chin with one elegant finger, in mockery of thought. "I suppose you could try an Unforgivable…but Dumbledore's golden boy is far too pure to touch dark magic." Her voice was filled with a delighted amusement.

Harry opened his mouth to shout at her, then thought better of it. He had used the Cruciatus, after all. He shook his head. He couldn't maintain his anger at Bellatrix. She might have killed Sirius, but it was Harry who had led him there. Deciding that the Ministry and their rules could go hang, he used a charm to close and lock his door. After a moment there was a series of thumps, and Harry added a silencing charm. He lay down on the bed, and tried to think of nothing at all.

Harry left his room in the early afternoon, unable to ignore his growling stomach any longer. He went down the stairs quietly, hoping to find some food without having to deal with Bellatrix again. As he turned into the kitchen, he bit back a curse. Bellatrix was sitting at the kitchen table, her back to him, staring at something in front of her. Harry considered coming back later, tapped the pocket where his wand sat and shook his head. He owned this house, after all, and Bellatrix couldn't do anything to hurt him. Probably. He walked past Bellatrix as casually as he could, and pulled the icebox lid up. It made a thump as it banged against the wall, and Bellatrix jumped in her seat. Harry glanced over his shoulder at her, and bit his lip to avoid smiling.

"Merlin's teeth, Potter," she snarled. She was breathing heavily, and Harry was pretty sure that the ferocity was a cover for her surprise. "You can't even walk like a proper wizard." Harry grimaced, and turned back to look in the icebox. It was empty. "There's no food, Potter," Bellatrix said. "As I tried to tell you. The elf won't make anything but mushroom soup, and it throws the leftovers away after every meal."

"Sorry you're not enjoying the food," Harry said absently, closing the icebox and twisting around to lean against it. "Pity it's not up to the high standard set by the Hotel Azkaban."

"My pain is your pain, Potter." Bellatrix bared her teeth in a parody of a smile. "This time."

Harry shifted his weight at the reminder. Sirius dead, Bellatrix gasping in momentary pain on the Atrium floor, and then Voldemort's arrival…he twitched his head to drive the memories away.

"Kreacher!" Harry snapped. The house elf appeared in front of Harry with a pop, spindly arms hanging by his side as he stared sullenly at the floor.

"Halfblood brat calls Kreacher," the elf muttered. "But Kreacher won't, Kreacher won't! Kreacher won't…" he trailed off into mumbled imprecations. Harry blinked down at the elf, not quite sure what to do. Kreacher had helped the Death Eaters on the night that Sirius had died, but…he looked so pathetic and worn down. Like Dobby, when Harry had first met him.

"Give him orders, Potter!" Bellatrix said impatiently. "To make ome decent food, for a start."

"Shut up, Lestrange," Harry said absently, still frowning downwards at Kreacher.

"Black," she hissed.

"Kreacher," Harry began sternly, then stopped to think. "Make some decent food for meals, will you? And keep the icebox stocked."

"That's not an order, Potter," Bellatrix said. "Make it explicit."

"Fine," he snapped, and glanced at her. "You, shut up." He turned back to Kreacher. "Make the food that people ask you for, and make it to the best of your ability. Don't throw the leftovers away." He paused. "Don't communicate with anyone except me or Dumbledore, and don't leave the house unless it's to follow an order."

"Oh, well thought out, Potter," Bellatrix said lazily. "Not banking the fire after the ashwinder's hatched, not at all." Harry's hands clenched into fists; he forced them to uncurl, and took a deep breath.

"Kreacher, please make me a corned beef sandwich," Harry said steadily. Still muttering under his breath, Kreacher shuffled over to the bench and snapped his fingers. A slab of meat, a loaf of bread, and a knife appeared in his wizened hands. Harry assumed that Kreacher had summoned them from storage – house elves couldn't just make food out of thin air. As far as he knew.

"Nicely done, Potter. You can control a deranged old house-elf. Sirius would be so—"

"Shut up!" Harry said. He took a step towards Bellatrix, wavered on the edge of taking another. "Don't say his name!"

"You knew him for a year or two, Potter," Bellatrix said in a low, ragged voice. "I grew up with Sirius, and I will speak of him as I like."

"You killed him!" Harry said. "Your own cousin."

"And I regret it. But this is war, Potter."

"That's how you justify it? What you did to Sirius, to the Longbottoms? It's war?" Harry stared at Bellatrix, sitting at the table, pale and composed. "That's bollocks. This war is bollocks, you're nothing but a twisted bitch who gets off on hurting people." Harry was vaguely aware that he was shouting now, but he was tense with rage, sick with grief, and volume seemed unimportant.

"Of course you don't understand what we're fighting for," Bellatrix said. "You've been brought up in a squalid Muggle hovel, with no idea of your bloodline or your duty to your family."

"I don't have a family," Harry said, his voice quiet again.

"They chose the wrong side," Bellatrix said stiffly.

"And what about you?" Harry said bitterly. "You act like Voldemort—"

"Do not say that name!"

"—Voldemort," Harry said again, more loudly. "Is still on your side! He threw you out! You had to run to Dumbledore. You sold your bloody cause out the minute "

"He will pay," Bellatrix said through clenched teeth. "He'll see that he was wrong to cast me away." She shook her head, tangled black locks shifting. "My…the Dark Lord is a treacherous fool, and I'll see him dead one way or another. But once I've had my revenge, my work begins again."

"Your work," Harry said slowly. He snorted. "Of course. Killing and torturing people because they've got the wrong parents—"

"Purifying—"

"No! Just because someone's born to magical parents doesn't make them better or worse, and even if it did that isn't grounds to kill people."

"Our society has stood for thousands of years," Bellatrix said. "And they care nothing for it. More of them, every year…we're fighting a war to defend ourselves, Potter."

"You think your society is better than Muggle society? You think you're better?"

"Of course I am," she said impatiently. "And so are you. Admit it. You're a breed apart from any fumbling mudblood."

"Well if you're so superior," Harry said, looking Bellatrix in the eyes, "why are you hiding under the Fidelius charm right now? Why did you spend thirteen years in Azkaban for a man who tossed you away like…" Harry groped for a suitable simile. "Like a house-elf."

Harry had been half-expecting Bellatrix to try and curse him again, and had ben confident that the Unbreakable Vow would stop her. Instead, she threw herself at him across the kitchen, hands curled into fists and a mad gleam in her eyes. A moment before she hit him, her whole body shuddered and tensed. When her muscles relaxed, Bellatrix fell to her knees on the floor.

"Shades take you, Dumbledore," she gasped. Harry crouched down so they were on the same eye level.

"And why," he said, "if Dumbledore is as weak and foolish as you Death Eaters – sorry, ex-Death Eaters – keep saying, did you swear to obey him like this?" He would have said more, the words pressing against his throat like acid, but Bellatrix burrowed her hand into his pocket and yanked his wand out. Harry made an inarticulate noise.

As Bellatrix jumped to her feet and turned to run, Harry grabbed her shoulder and pulled. She whirled and tried to lash out with an elbow, but her body shivered with tension again. Growling like a cat, she tried to pull out of Harry's hold. He held onto her shoulder tighter, grabbed her wand hand with his right hand and dug his thumb into the hollow of her wrist. She dropped the wand with a yelp, and suddenly threw her whole weight away from Harry. Unbalanced by the sudden movement, Harry staggered backwards and fell against the kitchen bench. He was vaguely aware of Kreacher making incoherent noises, and something touching his arm.

Bellatrix drew her own wand and cast something. Harry pushed off the bench and dived for his wand, but it skittered away from his fingers. She had enchanted it. Bellatrix backed towards the corridor, but Harry managed to pin his wand between his hands. Holding it between his palms, Harry raised his wand and cast a blasting hex at Bellatrix with all the rage he could muster. Her hasty shield wasn't enough to protect her, and the hex sent her sailing through the doorway to hit the wall in the corridor. Cancelling the enchantment on his wand and getting to his feet, Harry reflected that it was the second time he'd thrown her into a wall today.

He held his wand ready for a moment, but didn't hear any movement. He stepped through the doorway, and looked down at Bellatrix sprawled unconscious on the floor. With her eyes closed, her arrogance muted, she looked…peaceful. And tired. Something fell onto her face, and Harry realised that he was bleeding.

"Master has injured himself," a croaky voice said from behind Harry. He turned to face Kreacher, and frowned at the cut along his forearm. During the – it hadn't been a fight – during the scuffle, he hadn't noticed the cut, but now it was starting to throb.

"Yeah," Harry said dully. "I did." He glanced at Kreacher, at Bellatrix, and back to his cut.

*

Just so everyone's clear, Bellatrix is not going to be a sympathetic character. But I wanted to make it clear that she does believe in something beyond Riddle, even if she thought Riddle was the embodiment of those beliefs.