It only took Dudley three days to decide he wanted to try some magic for himself. Harry watched gobsmacked as Draco lent the Muggle boy his wand and talked him through a simple swish-and-flick. Of course, nothing happened; Dudley wasn't going to really learn any spells, but he seemed to enjoy the fantasy of trying. When he was tired of it, he gave the wand back to Draco and turning to Harry, admitted, "Well, I can sort of see why my mum hated yours so very much, I think. It would be pretty easy to get jealous, wouldn't it?"

Harry blinked, realizing he'd never really thought of it in those terms. Something inside him didn't want to, either. "Aunt Petunia wouldn't ever have seen much magic," he protested. "I mean, my mum wouldn't have done any when she was home on school vacations."

"Yeah, well Mum didn't like to talk about it, but she dropped a few hints over the years. She saw enough," Dudley merely said. "I'd probably be jealous of you, you know, if Marsha hadn't talked to me about it, about how people are all different, and that's just how it is."

"Jealous of me," Harry scoffed. "I can't do any more magic than you, right now, unless you count talking to Sals, and I somehow don't think you mean that."

"Defeatist," Draco murmured as he strolled past.

Harry ignored him, but Dudley didn't. "He's right, you know. Or at least, he says the sorts of things I can really see Marsha saying. You probably should have a more positive outlook about your magic. It's like my diet. I couldn't lose weight until I decided to, simple as that."

Draco turned around and beamed. "See, there now! You'll listen to your cousin, won't you? He's been seeing a professional therapist for . . . how long, Dudley?"

"Almost a year."

"Almost an entire year," Draco stressed. "And even he thinks you're doing this to yourself."

"Oh, that's rich," Harry scoffed. "You're taking a Muggle's word for what's wrong with a wizard?"

"Why Harry," Draco remarked, his smile sly. "You sound as though you have something against Muggles. I'd watch how I phrase things, if I were you."

"I don't have a problem with Muggles and you know it," Harry retorted. "Why don't you watch what you say?"

"I have been," Draco flatly announced. "If you tell me you haven't even noticed, I'll tear my hair out. Just think what a mood I'll be in, then."

Sensing that he'd really upset Draco, Harry murmured, "No, I noticed. I just can't tell how serious you are, about anything." He cleared his throat. "Listen, I heard you talking to Snape when I first got here, and you said it made you practically throw up even to think about having Muggles in your precious pure wizarding bloodline. But then you're actually nice to Dudley here, and he's as Muggle as they come. So which one is the real you?"

"I am actually listening to all of this," Dudley put in.

"Oh, sorry," Harry realised, chagrined. "I don't mean anything, Dudley. It's just that some wizards have a thing against Muggles. Not me."

"You do?" Dudley asked Draco, the question sounding so very hurt that Harry was tempted to go hug Dudley again. He resisted the impulse, but not just because behind the temptation was a wailing sort of mental pain warning him away. It was also the fact that Dudley wouldn't appreciate it. The other time had been different; Dudley had been deep in shock and crying.

Draco sighed. "I can't help it, after sixteen years of indoctrination on the subject. You're actually the first Muggle I've ever spent any amount of time with."

Dudley sighed and lay back on the couch, which Draco re-transfigured each morning.

"It's not so different from Harry's aunt and uncle hating him just because he had wizarding bloodlines, you know," Draco defended himself. He appeared to be talking to the room in general, but Dudley took him up on it.

"Sure it is," the Muggle boy insisted, staring at the ceiling. "They were scared of what Harry could do to them, though now it all seems sort of stupid, the way they went about things. Marsha and I talked about it. Mum and Dad really should have given you the nicest room and all that, and made sure you never had cause to curse them, if you ask me. But anyway, they were scared." Turning on his side, he cast a glare in Draco's direction. "But your kind, what do you have to fear from us?" Dudley made a scoffing sound. "Seems to me you hate us just because we exist, not because we're any kind of threat."

"Have you ever heard of the Middle Ages?" Draco icily inquired. "Witch burning was all the rage."

"Oh, come on!" Harry erupted. "We learned all about that from Binns. The Muggles were burning each other. Mass hysteria, remember? And when they did get a wizard, he'd just use a flame-freezing charm--"

"You need the to study the unedited version of the Middle Ages," Draco retorted. "You think they're going to teach the sweet, innocent little children at the school an ugly truth that just might drive young, impressionable wizards into the Dark Lord's camp? I don't think so, not as long as Albus Dumbledore heads up Hogwarts. There were real wizards burned to death, and plenty of them. Where do you think the contempt for Muggles came from?"

"A real wizard would just Apparate!" Harry shouted. "Or are you going to tell me that the Muggles cast anti-Apparition charms across the burning places?"

"Some wizards aren't so skilled at Apparition, as I'm sure you know," Draco heavily returned. "And there were other factors at work, but if you think I'm going to discuss them in front of a Muggle, you're not thinking much at all. Anyway, it's not just witch-burning that could happen to us these days. At least the killing curse just kills one at a time. We don't have weapons that can level whole cities, killing everybody at once, Muggles and Wizards alike."

"So what's your point?" Harry pressed, narrowing his eyes. "That you were right to be such a hate-filled little shite?"

"That there are real reasons why the Dark Lord's philosophy appeals to purebloods!"

"Even though he's a half-blood himself," Harry scoffed.

"Well, that's the thing about hate," Draco pointed out, his voice markedly quieter. "It's irrational."

"That's true," Dudley put in. "If anybody ought to hate Muggles, it would be you, Harry. How come you don't?"

Harry stared at his cousin, his green eyes shadowed. "I . . . I don't really know. Maybe because I learned so early on what it's like to be hated for something you are, something you can't help being."

"Oh." Draco paused a moment, then asked rather diffidently, "Did you get the book from Severus? Because it covers emotional abuse too."

"Maybe you should read it," Harry retorted. "I mean, for your own benefit."

"I did," Draco admitted, then turned away. "Dudley, do you play any chess? No? Hmm. Well, let me show you wizards' chess anyway. I think you'll like it."

Sighing slightly, Harry got the book from under his pillow and found his place.

-----------------------------------------------------------

Ever since that talk in Snape's office, Harry had settled into a new routine. Most nights, after dinner, he'd spend a few minutes, sometimes longer, chatting with Snape. The first night when he went back, things still seemed awkward, but after he realised that his teacher really didn't mind being interrupted, Harry realised he didn't have to have to bring some earthshaking problem into the man's office. It was all right to go in there just for company. To talk about nothing, it seemed. Sometimes, even, just to sit and read while Snape marked essays.

By then, his vision was largely recovered; he no longer needed any help reading and writing. He didn't even need the Elixir except once each morning. Sometimes when he woke up in the night needing to go to the loo, he thought he was blind again, but since he didn't have a light to see by in any case, he couldn't be sure.

"Book not keeping your interest?" Snape casually inquired one evening in his office.

Harry realised that he'd been staring into space for a while. He wondered how long ago Snape had noticed. Disconcerted, he dragged his gaze away from his teacher's piercing black eyes. "It's the book," he murmured, finally gaining enough presence of mind to look down at the passage that had sent him into a blue funk. One finger indicating a passage, he flipped the book around and leaned forward to push it across Snape's desk.

Snape raised an eyebrow and read out loud, "Dreams reveal the focal points within us, showing in concrete images our hopes, dreams, loves, and fears."

"I was wondering how much of the dreaming stuff in this book even applies to me," Harry admitted, "considering . . . um, how much did Remus tell you about my seer dreams?"

Snape set down his quill and capped the bottle of red ink he'd been using. "Enough."

Harry looked up, his eyes haunted. "The only thing that kept me sane on Samhain was believing that my dreams had to be right, Professor. They'd said I'd live past it, no matter what Lucius Malfoy did to me. I clung to that with all my strength."

"Excellent stratagem, in the circumstances."

"Yeah, but now I don't want the rest of the dreams coming true."

"Harry. I am certain that your friendship with Mr Weasley can withstand a bit of fisticuffs."

Harry sighed. "Remus really did tell you everything, I guess. But see . . . just the day before yesterday, I almost did hit Ron. Thanks for letting my friends come down more often, by the way."

Snape inclined his head slightly.

"Anyway," Harry rambled, "that was great of you, but sometimes I just can't believe how stupid and immature Ron can be. Almost the first thing he said to Dudley was, How's the tongue? which is just really cruel. It goes back to a joke the twins played on Dudley one time; they got him to eat some candy that made his tongue grow really long. Ten feet! Anyway, I just could not believe he would say that! I almost slugged him right there on the spot!"

"But you didn't."

"No. And see, I wonder if that was just it, then. That was my chance to punch Ron, and I passed on it. Would the future be that simple to change?"

"Quite possibly." Snape steepled his fingers together. "Divination isn't like Potions. I can't advise you with exactitude."

"Yeah, well I'm not asking Trelawney."

"No," Snape agreed. "Don't."

Harry nodded, and resumed his reading.

-----------------------------------------------------------

"This letters business is getting really old," Draco complained over dinner a few nights later. "Honestly, Severus, I need to talk to some of these people!"

"No," Snape replied, shaking his head for extra measure. "The mood in Slytherin is still too dire. Someone will provoke you, Draco. We don't need that."

"Look, I lost it with Pansy. I admit it. Shouldn't have hexed her so hard she flew into the wall and cracked her head open. What do you want, a gold-plated apology? It won't happen again!"

"A cranial contusion was the least of what you did to her," Snape asserted as he calmly set his spoon down beside his half-finished bowl of vichyssoise. "Lucius trained you for battle, I know. But this isn't battle, Draco, it is war. Sometimes the most substantive results come from working behind the scenes."

"And you don't trust my impulse control," Draco sniped, slamming his own spoon down so hard that Dudley flinched.

Severus raised an eyebrow. "When you have just dented my antique mahogany table? No, I don't."

Draco snatched his wand out of his pocket and repaired the damage. "You say I have to stay here until there's no more danger, but the danger won't lessen until you let me out, Severus. I used to have a lot of sway in Slytherin, you know. I could get it back if you'd let me apply my charismatic charm to the problem. I could convince people that Potter here's not so bad."

"Call him Harry," Snape instructed, reaching for his wand. "Ten points from--"

"I'm just saying it how I'll have to say it to them," Draco stressed.

Snape didn't finish the command to the house counters.

"We're never going to get out of here at this rate," the Slytherin boy continued. "You have to let me do something--"

"Mr Malfoy," Snape icily broke in, "You are labouring under a misapprehension. I do not have to let you do anything. You have to abide by my requests if you wish to continue living here. That decision is yours since, as you well know, you have been emancipated from all parental authority."

"I appreciate what you did, Severus--"

"Thank the headmaster. He is the one whose influence overcame your father's strident objections."

"I appreciate everything you're doing, Severus," Draco went on, raising his voice. "It's just . . . I want to do my part, too! Like I said I would! And I can't, not so long as I'm penned up in here."

Snape rose to his feet. "For now, your part consists of doing what I say, Draco. Write your letters. Keep up with your studies, and see to it that Harry gets caught up. I will know when the time is ripe for more direct action." Without another word, he strode toward his office.

Harry finished his grilled cheese sandwich and drank some milk. He wasn't sure what to say, especially not with Draco still fuming. Besides, he was getting a little desperate for some fresh air and sunshine, too. He could understand Draco wanting out.

"Christmas isn't too far off, you know," he finally thought to offer. "You know how most students go home for the holidays? Well, maybe the professor will let us out a little bit, then."

"Thank you," Draco sourly returned, "for pointing out that I no longer have a home to go to, for holidays or anything else. And what makes you think Severus wants to be stuck here?"

"Hey, Harry never got to come home at Christmas, either!" Dudley began, but Harry waved for him to fall silent.

"I didn't mean it that way."

"Well you wouldn't, would you? No offence, but the way this one talks," he hitched a thumb toward Dudley, "it sounds to me like you've never had a home at all. Some of us don't relish being stuck in the dungeons all through vacation."

"My point was that maybe we won't be."

"Yeah, sure," Draco muttered.

"Now who's being defeatist?" Harry lightly jeered, though Draco had given him something to think about, he really had.

Later, when Draco was reading and Dudley was moving wizard chess pieces and watching them smash each other, Harry went and knocked on Snape's open office door.

His professor shook his head at him. "I've told you before; you needn't knock."

Harry closed the door after he went in, which made Snape's brows rise up a tad. "Problem?" he inquired with deceptive mildness.

"Not really." Harry sat down in his usual chair and gravely regarded his teacher. "Just thinking. You're actually related to Draco, aren't you?"

"I'm sure I could ascertain the exact degree given an extensive family tree and several hours with which to peruse it," Snape dryly admitted. "But yes. How did you come to this stunning bit of knowledge?"

"Sirius told me that all the pure-blooded families are interwoven."

"As indeed we are. The Potters included."

"Right," Harry agreed. "But see . . ." He leaned forward. "I was thinking about Christmas, actually. I've always stayed at Hogwarts for the holidays. Much better than going to the Dursleys, not that they ever wanted me to, of course. But . . . er . . ." Harry took a breath, then plunged ahead. "Well, I was thinking that you shouldn't be stuck here on my account, and Draco's bound to get pretty depressed when it really hits him that he can't be at his usual family whatever, besides which he's already depressed being down here so long with just me for company all day long."

"This reminds me of your more garbled answers in Potions class," Snape observed. "What in Merlin's name is your point?"

Harry swallowed, nervous because he knew he was intruding into areas where he had no business. He hadn't seen much about Snape's family in that pensieve the year before, but what he had seen hadn't been pleasant. Still, decades had elapsed since those memories had been forged.

"Harry?" Snape sharply questioned.

"Sorry," he quickly came back. "Um, well I just wondered what your usual Christmas routine was, because whatever it is, I think you should follow it and take Draco with you, that's all."

"Follow it," Snape blankly repeated.

"Yeah," Harry urged, surprised that he would have to explain. "You know, get away from Hogwarts, see your Mum and Dad, or . . . um, whoever it is you usually see. You must have some family, I'm thinking."

Snape leaned back in his chair and crossed his hands across his chest. "You are proposing I should leave you here alone? Your cousin will be gone by then, I hope you understand."

"Uh, yeah, I understand that," Harry murmured. He'd sort of got used to having Dudley around, he realised.

"Do you have any concept how daft a notion your suggestion is?" Snape inquired, his eyes beginning to glare. "You, in the Slytherin dungeons, completely alone!"

"Well, they should be warded with the blood sacrifice by then--"

"You can't even Floo for meals without a wizard's assistance!"

"I thought we could just arrange for Dobby to pop in each morning and night and see what I need--"

"I did not think you were finding my company so intolerable," Snape glacially remarked.

"It's not that," Harry protested. "I mean, I don't! It's just . . . I just realised you would probably have plans if I wasn't in the way, and I don't want to wreck your Christmas, that's all!"

Snape's hands sought the arms of his chair, and gripped them. "You aren't in the way."

"I . . . " Harry didn't know what to reply. He didn't actually know why he'd said that. Or said it like that. It sounded stupid when he heard it repeated back out loud, though it made perfect sense inside his own head.

"As a matter of fact," Snape casually volunteered, "I do have holiday plans. I plan to spend the Yule season with you and Draco, if that's quite all right with you?"

"Um, yeah." Harry smiled, a little bit chagrined.

"Have you any other suggestions for my social calendar?" Snape snidely went on. There was a hint of a smile about his mouth as he said it, though, so Harry didn't figure the man was really all that angry.

"Well, I don't know that it needs to be in your calendar," Harry put in, "but I still think Draco could use a change of scenery."

"Just Draco?"

"I already told you that I'm going stir-crazy," Harry reminded him. "But I think it bothers Draco more. I mean, he can't even have his friends come down! Um, does he have any friends left?" When Snape didn't answer, Harry exclaimed, "Oh, just sneak him out onto the Quidditch pitch or something, would you? Let him go flying! You can borrow my invisibility cloak if it'll help."

"I'll take it under advisement," Snape dryly remarked. Then, with a strange glint in his eye, he offered, "As I recall, your spelling is adequate for your age. Now that your vision has returned in force, would you be willing to assist me with this endless pile of essays? You could check over the first years' efforts, correcting their atrocious spelling."

"Sure, all right," Harry said, though he had to add, "you know, the pile is only endless because you assign your students way too much work."

"Ah yes, I had forgotten you considered yourself the foremost authority on instructing adolescents."

"I'm just saying, there's more to life than Potions."

"There is," Snape agreed, shooting him a wry smile. He quickly sorted though the parchments and drew out a set for Harry to use. "But where would your beloved werewolf be if some of us weren't devoted to pursuing excellence in the field of Potions and promoting it in others?"

"Touché," Harry murmured. "Hey, speaking of Remus, you said yourself my vision's no longer much of an issue. When can I see him?"

"Determined to surround me with Gryffindors, Potter?"

"Hey, I'm the one who's outnumbered here," Harry protested, taking the quill and ink his teacher pushed across the desk. He noticed the way Snape had sidestepped his question, but decided not to push things. Not just yet, anyway. Scooting his chair up closer to the desk, Harry frowned down at the first essay. "You can't be serious. It's almost Christmas and this girl still spells Potions with s-h-u-n-s?"

"Leona Ellingsworth," Snape said without glancing Harry's direction. "Hufflepuff. What can you expect?"

Surprised at Snape's ready answer, Harry pressed, "Oh yeah? Well, what little quirks do my essays tend to have?"

The Potions Master smirked slightly, even as he continued writing commentary on a seventh-year's paper. "You've yet to use a transition, you ramble on for three paragraphs before deigning to mention your thesis, and for some reason you believe that Quidditch analogies will shed some light on the topic. Allow me to enlighten you: they don't."

Harry laughed, remembering a few . . . no, a few dozen, comments to that effect. "What about Ron?"

"Apart from the fact he thinks that ten inches equals a foot?"

"And Hermione?"

"Addicted to the words therefore, insofar, and of all things, hitherto." Snape lightly shuddered.

One more, Harry told himself. Then he'd stop.

"What's wrong with Draco's essays?"

Snape stared at him for a moment, then levelly admitted, "Generally nothing but that ridiculous calligraphic script he favours."

"He cheats, you know," Harry offered. "He's got a spelled quill to do that fancy script for him."

"That is not cheating. It's being--"

"Slytherin," Harry finished, just as Snape also said the word.

"Mmm," Snape agreed. "Though it would be better for his work to look less like a work of art. Harry. It is good to talk with you, but I really do need to mark these, now."

"All right, Professor." Harry grinned, and corrected spelling without much comment from then on.

-----------------------------------------------------------

"Blood," Dudley blankly repeated late one night.

"Yes," Snape patiently explained, just as if he hadn't just gone through the whole thing twice already. "The spells for the warding involve specific demands of the participants. You must have a nearly continuous physical presence here for the magic to remain active. Your blood integrated into the spells will achieve this."

"I'm absolutely positive my Mum wouldn't have agreed to er . . . any hocus-pocus like this. I mean, it sounds like . . ." Dudley shivered, and gripped the edge of the dining table. "Voodoo."

A muscle twitched in Snape's jaw, but he was doing an admirable job of repressing his yell-at-imbecilic-student response. Dudley wasn't his student, and they needed him, so terrorizing him was out of the question. Too bad Neville couldn't fall into that category, Harry reflected.

"Transferative warding wouldn't have been required at Number Four Privet Drive, as the proxy for Lily Potter's blood actually did reside there," Snape began, but Draco cut him off.

"It's like this," he explained, leaning over the table. "Your Mum really lived there, see? Her just being around would make the spells work, so all she had to do was take Harry in. This is a little different. You don't live here, so you have to leave a little bit of yourself behind, or the magic'll fall apart. Does that make sense?"

Dudley opened his mouth, a long "oh" sound coming out. Then, he asked, a little diffidently, "Why blood, though? I could just clip a fingernail, couldn't I?"

Draco answered that one before Snape could start in with big words for bigger concepts. "Blood's actually better. It's a powerful magical force, which explains why what Harry's mum did for him is called a blood-sacrifice, see? Besides, all we need is a couple of drops."

Dudley measurably relaxed. "Oh, all right. Why didn't he say so? I can do that."

"Good," Draco approved, beaming an encouraging smile. Perfect teeth, Harry thought, then immediately discounted that as more Slytherin cheating. Magic braces, something like that. "So, are you ready then? We won't need the blood for a few minutes. First Severus has to do the incantations and draw power from the air and stuff like that. Then he'll ask you some questions, and then, we'll seal the warding with your blood, and voilà, it'll be done."

"Questions?"

"Yeah, they're sort of like vows. You have to agree to all this to make the magic work."

"I get to make the magic work," Dudley marvelled, his eyes sparkling a bit.

"Yeah, we couldn't do this without you, Dudley," Harry put in, nodding. "So thanks. It means a lot. With the spells in place, nobody who means me ill will be able to get into these rooms."

"It's all just a way for me to make Severus let me live in Slytherin," Draco joked, but his silver eyes were wary as he watched Harry take in the comment.

Harry glanced at him, but said nothing in reply.

"Well, even if she didn't have to . . . er, bleed, I still can't really see Mum letting wizards into her house to wave wands all around."

"No, she wouldn't have," Harry agreed. "All she had to do was take me in. But she was closer to the original power of my Mum dying for me, Dudley. I mean, she knew her sister, right? Grew up with her, all that. So for her, the transfer was sort of natural. Professor Snape has to do more formal magic to transfer my Mum's blood sacrifice to you. It's pretty complex stuff."

"I think you offended Severus," Draco said in a stage whisper. "It's interaxial multidimensional sorcery he's about to perform, not complex stuff."

"No wand waving or silly incantations?" Harry laughed.

"Be quiet, both of you," Snape instructed. "Just watch. Maybe you'll learn something. Dudley. I need you to stand next to me."

And so it began. Harry stood up from the table and backed away as he watched Snape begin both wand waving and incantation, but none of it was silly. He chanted rhythmically in a language that sounded somehow Latin, and yet older than that as he pointed his wand at all the corners of the room. Silver threads formed from his wand and spun out to those corners. The threads wove themselves into a shimmering spectral fabric that began to coat the walls.

Draco pulled Harry away from the granite before the shining tapestry touched him. Harry couldn't help what happened next. He flinched violently away, stumbling so severely that his feet slipped out from under him. He landed on his arse, his skin feeling like it had been doused with boiling oil, even though Draco had only touched sleeve, not skin.

He looked up, only to see that Draco looked absolutely ashen, his silver eyes haunted.

Harry remembered then, what Snape had said, that Draco was quite literally terrified that he could someday be thrown to the wolves on Harry's say-so. Harry certainly didn't trust the Slytherin boy . . . not even close . . . but he didn't want Draco thinking he'd lurched away because of that. It was more that he'd been startled. Even Snape's hand on his shoulder could disconcert him if he wasn't expecting it.

Harry couldn't explain all that without speaking and disrupting the spells being cast, so he did what he could. Biting his lips to hide his grimace, he extended his hand towards Draco.

The Slytherin boy's eyebrows rose, and for a moment he just stared, but then he helped Harry up.

Snape began walking, continuing his chant, entering every room and spelling it in the same way, one hand on Dudley's elbow keeping the Muggle boy with him all the while. Following along, eyebrows raised, Harry noticed that Snape warded the ceilings and floors, too, the silver shimmer of the phantom tapestry acquiring an aura of gold as it continued to weave itself thicker.

When the entirety of Snape's quarters were coated in the stuff, all of them stepping in it despite Draco's earlier caution, the Potions Master fell to his knees and incanted one last spell.

Instantly, all the warding flew back towards his wand to coalesce into a glowing ball floating in the air above Snape's outstretched hand.

"Dudley Dursley," he said, the English sounding harsh after all those soft Latinate sounds, "do you give consent that this domicile may host the powers that will protect and preserve your mother's sister's son, Harry James Potter?"

"Yes," Dudley whispered, looking sort of appalled, of all things. Harry figured that just came from him never having seen any ritual magic before. Draco's dancing candies definitely didn't count.

"Do you consent to yield up blood such that his mother's love-sacrifice may continue to reside in this place?"

"Yes," Dudley said again, and that time, he just looked plain scared. Probably the mention of the blood.

"Harry," Snape said, prompting him. They'd discussed this. It was taking all Snape's power just to hold the warding spells in place for the blood binding. That pulsating sphere above his hand was made of spells. Snape couldn't both keep it coalesced, and drip the blood atop it.

Stepping close, Harry took the ceremonial blade Draco held out, and with an apologetic wince, made a tiny slash in Dudley's palm. Holding his cousin firmly by the wrist--and ignoring the tremors that caused him--he turned the palm to face the floor and let the blood drip onto the warding spells Snape was holding steady.

Instead of being absorbed and made a part of the magic, as they all expected, the blood fell straight through the luminous sphere to drip onto Snape's own palm.

And then the concentrated magic in that sphere wavered, the ball undulating, unravelling, and vanishing from existence.

Snape uttered a long, low curse, and shakily pushed himself to his feet.

Draco stopped breathing.

Dudley rubbed his sore palm and looking around, said, "Is that it, then?"

It was left to Harry to conclude out loud, "I think it didn't work."

"No, it didn't," Snape concurred, his tone rather bleak. "The physical manifestation of the spells should have turned the colour of blood, and then, the colour of your mother's love, and flown back out to melt into the very stones that comprise these rooms."

"What went wrong?" Harry pressed.

Snape didn't answer that. "Draco, Floo the kitchens for something light to eat and drink." He sat at the dining table and beckoned everyone to join him, shaking his head at all questions until he'd drunk a full cup of tea and eaten a couple of finger sandwiches. Then he observed, "The form of the incantations was definitely not the problem. I think it must lie in the applicability of the spell."

"You said Dudley's blood could only be used to ward a personal residence," Harry remembered from their conversation in the hospital. "Maybe this doesn't count as one, even if you have been the sole occupant for years and years?"

Snape shook his head. "I did some other spells to check for that. The rooms here believe I'm the owner."

"Then that's the problem," Draco pronounced, waving a hand toward Dudley. "He should be the owner, surely, if he's going to be the key to warding this place. We're looking for things to be parallel, right? Harry's aunt owned her house, after all."

"But she didn't," Dudley gulped. "I mean, the bank owned most of it. Mortgage."

"Mortgage," Draco blankly repeated.

"They borrowed money to buy the house," Harry explained.

Draco's expression adopted a faintly sneering superior air, as if he was thinking, Borrowing money, how very vulgar.

"If your aunt could ward a place she didn't literally own, then Dudley's lack of ownership here can't be at issue," Snape mused out loud, his black eyes calculating possibilities. "And with the physical presence of his blood bonded to the spells, his lack of residence shouldn't be the problem, either. So why did the spell fail?"

Dudley suddenly laughed, a smile breaking out on his fat face as he stared at the three puzzled wizards. "It's him," he announced, pointing a pudgy finger at Harry. "He's the difference between that situation and this one. Isn't it obvious?"

Snape glanced at Harry, who only shrugged. "Yes?" the Potions Master prompted.

Dudley leaned his elbows on the table. "Of course your spells wouldn't work," he explained. "Harry was supposed to be living on Privet Drive. We were his family, bad as we were at it. And the spell is a family thing, isn't it, his mother's blood and all that? Harry belonged with us, had a right to be with us. This place is just a set of rooms to him. The blood dripped straight through that gooey magic thing because it saw that he doesn't have any real right to live here!"

Snape stared at Harry for a long moment, his gaze piercing as he considered that argument. Then, without any warning, he shoved his chair back and strode for the Floo, his robes billowing. Curious, the three boys stood and followed.

Snape threw a handful of powder into the fireplace, called for the headmaster, and waited until the man's head appeared in the flames. Then, he had just one question.

"Albus, if you bring your considerable influence to bear, how soon can I be signing adoption papers on Harry Potter?"