A/N: Sorry I didn't post this sooner. I fully intended to but exams are making me stressed and that means I forget things. Anyway, I hope you like this chapter, cause believe me, things are going to get worse...

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Chapter 37 – Breaking point

Harry glanced at Ron, who looked just as nonplussed as him. Cautiously, he walked over to where Robert was.

"Is she ok?" Robert looked up at him, brown eyes betraying his fear.

"No."

"What's wrong with her?"

"I don't know." He ran a shaky hand through short blond hair and swallowed hard. "We've got to get her out of here."

"But the entrance sealed up behind us," said Harry, casting an eye around the dark chamber. "And we haven't seen any other exit."

"Well we're going to have to find one," said Robert quietly, reaching out a gentle hand and brushing the hair away from Katherine's face. "Katherine? Can you hear me? We're going to get you out, ok? Don't you go giving up on me, all right?"

"Uh, Robert?" Robert looked up, scowling at Hermione.

"What?" Hermione gestured nervously towards the Inferi and he swore; the shield charm was fading and the group was advancing. "You three get back," he ordered, pulling out his wand and glancing anxiously at Katherine, still huddled on the floor. He needed to get her out now and find Remus or Severus or someone who could get through to her before she withdrew completely, because if that happened...well, he remembered only too well what she was like last time and he still didn't know how she'd snapped out of it then..

He got to his feet and faced the crowd of Inferi, trying to work out how many of them there were; twenty at least, he guessed. There wasn't any more time to waste, however, because they were getting nearer and Katherine wasn't in any state to move, so he drew back his wand, ready to fight, but just as he did so, someone blocked his path.

He looked into eyes as dark as midnight and fought the urge to take step back. She had her wand pointed at his heart.

"Katherine?"

"Put your wand away."

"Kat-"

"Do it. Now."

"But-" he faltered under the gaze of those eyes but didn't lower his wand. "Katherine listen to me, we're going to get you out of here but we need to destroy them first."

"If you don't put your wand away within the next five seconds I will make you do it, and you really don't want that."

"Katherine-"

"Three seconds."

"Fine, you want to kill me, then do it," he challenged, glaring at her. "I'd rather be killed by you than by them."

"They won't kill you," said Katherine evenly, in that same dead voice. "Not if you run."

"Run? Run where? There's nowhere to go and they'll keep coming after us – they don't give up. We've got to get rid of them now."

"No."

"Why not? What the hell's wrong with you?" he yelled, gaze flicking nervously to the group who were only a few feet away now.

"You so much as lay a finger on them and I'll kill you."

"Katherine, they're already dead, what does it matter what happens to them?" he pleaded, edging away as the nearest Inferi reached out a shriveled hand towards them.

"No," whispered Katherine softly, and he thought he saw tears glistening in her dark eyes, "they're not."

"What?"

"They're not dead. Look at their eyes, Robert, they're not dead. He used Inopia and made them Inferi and stuck them down here where no one will ever find them and they're not dead." She was crying now, tears running unchecked down her pale face and her next words were said so quietly that he nearly missed them. "And it's my fault."

"No," he said fiercely. "It's not-"

"I made it up," she shouted at him, eyes blazing with fury and hurt and despair. "I told him there were things worse than death and I made it up to prove it and now he's gone and used it against me."

Behind Katherine, the mass of Inferi had stopped, pressed up against an invisible wall and in the light emanating from the white gold pillar behind him, he could see the faint outline of shield charm. He frowned and saw Katherine's eyes dart over his shoulder; curious, he followed her gaze and saw the three teenagers with their wands out, maintaining it. Maybe they weren't so useless after all.

He returned his attention to Katherine, her last words ringing alarm bells in his head.

"Against you?"

Katherine just looked at him, eyes burning with hurt and hatred. He frowned, surveying the ranks of Inferi behind her, trying to search the rotting faces for one he knew, because that was what she meant – she knew one of the undead standing there, clawing at the barrier that prevented them going any further, and if he didn't do something about it soon, she was going to go back to that state of barely controlled insanity that she'd slipped into after becoming a Death Eater and this time he wasn't sure she'd be able to come back.

"We've got to kill them," he said at last, and she shook her head violently.

"No-"

"Yes," he said firmly. "We can't leave them like this, you know that."

"But I can't..." she trailed off, squeezing her eyes shut in an attempt to stem the flow of tears. "I can't," she said softly, shrugging her good shoulder. "Not her."

"I'll do it-"

"No." She shook her head, taking a deep breath. "No." She looked up at him, searching his face earnestly. "Did you mean it? That you'd rather be killed by me?"

"Yes," he replied quietly. "If I had to be killed, I'd rather it was someone I knew. Someone who was doing what had to be done because it was the best thing to do." She smiled sourly at this.

"You sound like Reg."

"Regulus?" he asked, frowning, but she'd already turned away towards the Inferi.

"When I say go, drop the shield charm and run," she said softly, glancing back over her shoulder at the trio. "Understand? Get as far away as you can. You too, Rob."

There was a slight pause, then Harry glanced at Ron and Hermione and nodded. Katherine looked at Robert, who held her gaze for a moment, deliberating.

"Are you sure about this?"

"I don't have very much choice, do I?"

"I told you, I could-"

"She's my mother, Robert. I'm doing it." Robert's eyes widened and he looked again at the ranks of the half dead, trying to discern a female with black hair or blue eyes but finding none. "Adoptive," murmured Katherine, gazing soberly at him.

"Right," he said quietly. "Ok."

Katherine watched him for a moment, then turned around, wand raised.

"Go."

Robert felt the blast of heat from twenty meters away but kept running. The trio were just ahead of him, running flat out towards the other side of the chamber. They didn't stop till the reached the smooth stone and collapsed on the floor, gasping for breath. Robert leant on the wall, almost bent double and tried not to be sick.

"D'you think she's all right?" asked Ron eventually. "I mean, that spell – if we could feel it-"

"She can protect herself," said Robert softly, peeling himself away from the wall and looking at the young boy.

"But did she want to?" asked Hermione quietly, sitting hunched on the floor, knees drawn up to her chin. Robert looked sharply at her, frowning.

"She won't rest till the Dark Lord's gone," he said firmly.

"Is it safe to go back?" asked Harry, standing up shakily and squinting in the direction of the pillar of light.

"What else is there to do?" replied Robert heavily. Slowly, the four of them made their way back in silence. Robert wondered if he'd done the right thing, leaving her to deal with things on her own, but he deep down knew he'd had very little choice. If he'd tried to stay, she would have used Imperius or something to make him leave. She was in that sort of mood.

By the time they'd walked back to where the Inferi had stood, Katherine had gone. Robert looked around but couldn't see her anywhere.

"She's not-?" Hermione trailed off, gesturing helplessly towards the piles of ash littering the ground.

"'Course not," muttered Robert, trying to sound confident. Katherine wouldn't give up like that, she wouldn't. She'd want revenge on her father for what he'd done and that might make her reckless, but she'd make sure she didn't die. He looked towards the central pillar of churning light again, half raising a hand to shield his eyes, and then he saw her. A small dark figure, silhouetted against the glow. Hurriedly, he made his way over to her, slowing as he approached.

She was crouched on the floor, peering closely at the glimmering light. He was about to say something, but she got there before him.

"It's ether." He started, staring at her.

"What?"

"Ether," she looked up at him and his heart sank when he saw the look in her eyes. He had hoped she might have recovered a little with the Inferi gone but if anything she seemed worse; now she was just hiding it better. "It was a concept of Aristotle, the Greek philosopher. You could call it the fifth element." She smiled, ticking them off on her hand, "Fire, water, earth, air and ether. It's how he's protecting his horcruxes." She looked past him as the trio trailed up, looking understandably nervous. "The locket was in the middle of a lake, wasn't it, Harry?"

Harry nodded, glancing uncertainly at her; she smiled brightly.

"Right, so that's water, and Ravenclaw's statue was on a plinth underneath Riddle's tomb, with no way to reach it except by flying – that's air. And Dumbledore found Salazar's ring in the Gaunt's old house, yes?"

"Yeah," agreed Harry. "But he didn't say where it was – just that it was protected."

"So we don't know that one for sure, but I'd be willing to bet rather a large amount that it was buried." Katherine grinned again, and Harry couldn't help but feel there was something wrong about that smile. "So that's earth, yes? Which leaves fire and ether, and this definitely isn't fire."

"But there are six horcruxes to hide," said Hermione nervously. "And there's only five elements."

"Yes, but he was keeping the diary out in the open, right?" said Katherine patiently. "He wanted it where he could see it - that's what I'd do. If I was splitting up my soul and hiding bits all over the place, I'd keep one near me for safe keeping. After all, I don't want someone coming along and destroying all of them without me knowing, do I? I'd want the last one where I could see it, so even if all the others are broken, I'd know I was safe until that one went, and I could prepare – maybe make another one."

"So he's keeping an eye on Nagini, now?" asked Ron, brow creasing into a frown. "Because he knows the diary was destroyed?" Katherine nodded, squinting thoughtfully at the pillar.

"That's why once we've killed her, we've got to go after him straight away so he doesn't have a chance to get ready."

"That also means there's a spare hiding place," said Robert quietly. "There might not be a horcrux, here, Katherine. Not if it was where he planned to keep the snake."

Katherine looked steadily at him for a long moment, then turned back to the pillar without saying anything. He frowned, wondering what she'd do if this trip turned out to be for nothing, then Harry asked quietly:

"What exactly is ether?"

"It's supposed to be what the heavens are made of," answered Katherine softly, sitting back and gazing serenely up at the seething pillar. "It doesn't exist, not really, not as Aristotle thought anyway, but... Well, this is what it would be if it did exist." She smiled faintly. "It's Greek – really should be aether, with an 'a', meaning 'that which is ablaze'."

"How do we get past it?" asked Robert, eyeing it doubtfully.

"Don't know," replied Katherine cheerfully, getting to her feet. "I guess we just walk through it."

"Is that possible?" She looked at him, lips curling into a smile that didn't reach her eyes.

"Only one way to find out."

And she stepped through. Robert swore loudly, darting after her and trying to catch her hand but she was through before he'd gone more than a few paces. He looked back at the trio who were looking worriedly at him and sighed heavily wondering what on earth had possessed him to agree to do this.

"There doesn't seem to be any other way out," said Harry quietly, studying the pillar of light critically. "Maybe it's just a test of nerve."

"And maybe it's not," said Robert brusquely. "We don't know anything about ether – I've never come across it and the only person who seemed to have any idea about it is stark raving mad because she's just been forced to kill her own mother."

"So all in all, not one of our better days, huh?" said Ron quietly, after a long pause. Robert looked sharply at him, and he shrugged. "Look, like Harry said, it's not like we've got much choice and so what if we don't know about ether? Katherine said it's not meant to exist so it's not like we could have prepared anyway – there's probably not a lot known about it."

"But there might be something-" began Robert, before he was cut off by Hermione.

"Hogwarts has got one of the best collection of magical books in Europe and I've never seen anything about it there."

"And you've read every book in the library, I suppose?"

"When we found out about the horcruxes I went through all of the restricted section looking for information and we never came across ether when we were researching for Harry's Triwizard Tournament tasks, either." She looked defiantly up at him, face pale but determined. "So yes, together we have read a large majority of the books in there."

"And you said yourself she won't rest till she's destroyed Voldemort," reminded Harry. "She may be mental but she's not stupid."

"Of course she's not stupid, but you don't know what she was like last time," said Robert through gritted teeth. "Intelligence has nothing to do with it. Bellatrix is clever but that doesn't stop her being a raving lunatic and Katherine's...well she's never been all right, not really. She's not...normal. Even when she first came to Hogwarts she wasn't right – she was quiet and no one really spoke to her but she didn't care.

"She just sort of sat in a corner and did homework or wrote home, and went completely unnoticed by everyone and then in fifth year she suddenly starts going out with Leon Wilkes and that gets everybody's attention and then-" he hesitated, smiling sourly. "You know that phrase – 'it's always the quiet ones you've got to watch out for'? You know why you should watch out? It's because one day they'll turn around and say something and that's when you realise that in all those years you were ignoring them, they were watching you." He sighed, running a frantic hand through his blond hair, then stopped abruptly, frowning. "She said I sounded like Regulus. Why did she say I sounded like Regulus?"

The trio stared at him blankly, and he wondered vaguely whether he wasn't going a little insane himself, changing topic so suddenly, but it seemed important. What had he been saying when she'd said that? Something about Inferi, wasn't it? He hadn't really been paying attention to his words at the time – he was just saying anything and everything to try and get her to stop pointing her wand at his chest.

"You could ask her," said Hermione gently. "But we'd have to follow her to do that."

Robert shook himself mentally, trying to refocus on the task at hand. Follow Katherine – go through the ether, even if they didn't know what it would do or even whether there was a horcrux waiting for them on the other side.

He looked at the three teenagers in front of him and wondered how many times they'd done this before, faced unknown dangers together with the odds stacked high against them. He wondered what it felt like – to be on the right side for once, doing what was right because nothing else would do.

Even Katherine knew that wasn't the reason he was here – she'd not even tried to pretend otherwise when she'd brought Regulus' research to his house. He didn't care about the war – what did it matter to him if muggles he didn't know were killed – but as long the Dark Lord lived, his family was in danger and he couldn't have that. Katherine was doing it because Regulus asked her to, and probably for Remus and Severus as well.

But these three, these three weren't doing it for any of those reasons. Yes they wanted their family and friends safe, but that wasn't their main aim – they wanted to stop the Dark Lord because they believed what he was doing was wrong. Even Potter, whose part in this whole affair was decided before he was even born, was doing it of his own volition.

Sometimes he thought he was the only sane person in the world.

"Come on, then," he said tiredly. "We've only got everything to lose, right?"

And he turned around and walked through the ether, not because he wanted to, not because he didn't have any other option, but because Katherine had done it, and he'd follow her anywhere.

Even if she was insane.