Summary: Harry doesn't necessarily expect a polite "thank you" after saving Daphne Greengrass and her younger sister from falling to their deaths, but he definitely doesn't expect the stream of verbal and magical curses he gets instead. His surprise is nothing compared to hers when her curse fails, though, and that discovery propels the two into a whirlwind week of legal loophole abuse, awkward lust, and weaponized Pureblood etiquette lessons.

[Author's Note: This takes place in a slight AU where all of the Death Eaters captured after the Battle of the Department of Mysteries escaped after only a few months, rather than a full year. Other than that, the only thing truly incompatible with canon through the start of HPB is that Astoria is four years younger than Daphne rather than two, but household wards are probably stronger than JKR would describe them if you asked her, binding magical marriage contracts exist, and inter-house political agreements have more teeth than they probably did in canon.

This story starts near the beginning of HBP and concludes a week or so later, with an epilogue to cover how things play out for the rest of that school year. There's some lemony content in Chapter 2 that survived editing because I think it's genuinely important to the plot.

Trigger warnings: Death Eater crimes (discussed), graphic violence, sexual abuse (discussed), suicide (discussed and attempted)

Thank you to Volksbrot for the extensive beta work and to Wake the Dragon for some thoughtful comments!]

Chapter 1: If You Bring a Friend, It's Murder

Curfew came and went, leaving Harry right where he wanted to be: alone under the walls of Hogwarts and the Scottish stars to contemplate how much he hated himself. He had spent the whole day putting together a mental "to-brood" list and he wasn't going inside until he'd worked his way through at least the start of his sixth year at this death trap of a school. So Dumbledore wanted to show him how Riddle had a tough life? Harry would play misery poker any day of the week against that whinging pillock and raise every goddamn hand.

Also, his nose still hurt. Fucking Draco. Why was Hermione so worked up about the used textbook he'd just gotten and not the literal baby Death Eater plotting to murder them all in their sleep?

Harry looked up at the stars and took a few deep breaths, trying to remind himself that he'd scheduled tonight for self-loathing. Anger at his friends and enemies was on the to-brood list for the coming weekend. He made a mental note to add "Hermione's list-making tendencies rubbing off on me" to the weekend list and was about to start walking again when a shadow launched itself into the sky above him.

His wand was in his hand before he could even process what he was seeing. The shadow was roughly the shape of a heavy-set human and definitely falling, not flying. A hawk in a dive still "flew," but this person was only incidentally airborne on their way to meet the ground one last time.

Harry tried to keep track of the spells that had saved his life in the past, even though he never thought he'd use some of them. "Arresto Momentum" had been one of those until approximately thirty seconds before he uttered its words and guided the falling student to the ground about five yards in front of him.

Someone a few inches shorter than him rose to their feet, leaving a package of some sort...no, an even smaller student motionless on the ground at their feet.

"Oh, you little fucker." Her voice was oddly familiar. "You skrewt-molesting git. What the hell are you doing here?"

Harry blinked. He'd been trying to keep an open mind about what kind of reaction he might have gotten, but he was neither prepared for this one nor mentally able to handle it the way he might have last year, before...before the Department of Mysteries. "Fuck you very much then," he said, trying to push the memories back out of his head. "Most of the people I've saved were capable of not being a prat about the whole 'rescue' thing. Would you like them to give you some pointers?"

She snorted. "Harry fucking Potter. Just my luck that I'd time this to run into the one Gryffindor who really believes all of that crap about their 'bravery' and 'heroism.' Next time, just let me splat, Potter."

OK, so probably a Slytherin. Wait. "Daphne Greengrass?" He hadn't interacted with her much, but he'd never seen her anything like this blunt and caustic before. She'd always struck him as cautious, watchful, and proper, the sort of person who either avoided arguments or won them before they started. Then again, whatever had driven her to suicide had probably reduced her incentive to maintain her facade.

"In the lamentably intact flesh." She made a curtsey to complete the introduction. Even in the dark her mockery came through, but Harry was too distracted by the attention her motion drew to her legs to really care. Even when insulting him she was still stunning, the sort of trim, blue-eyed blonde girl who could have been a model for Witch Weekly should she have deigned to lower herself to such a thing.

She was also still talking, and Harry forced his attention back to her words. "This lump is my little sister Astoria," she continued. "Now, if you'll excuse me, I have to haul her heavy ass back up the tower somehow and try this again. I'd say it was nice talking to you, but the only good thing that's come out of this conversation is that I got to tell you off before I died."

"You know," Harry said, "last year at this time I'd have tried to stop you, but after the last twelve months I just don't care. Go ahead and jump if you want, but it would be murder if I let you take Astoria."

"Oh, OK," she said. "I'll just nip upstairs, then, and Petrific-ouch! What the actual fuck, Potter?"

In the dark, Harry hadn't even seen the wand in her hand, but he could hear it clatter to the ground as she yelped. "Serves you right," he said. "What happened?"

"I thought you did!" she said.

The lump at her feet stirred. "Who did what did?" Astoria asked sleepily. Harry vaguely remembered her being frail, skinny second-year Gryffindor with an infectious smile and unruly brown hair.

"Merlin's pants!" Daphne said. "I'm absolutely shite at curses and now she's waking up."

"Daph-nee," Astoria said reproachfully, "you promised not to give up."

"I'm not giving up," Daphne hissed. "It's over, Tori. We never had a chance."

Astoria started climbing to her feet. "There's always a chance." She passed Daphne her wand back as she stood.

Harry couldn't decide whether that level of sisterly trust was heartwarming or just insane. "Could you tell me what's going on? I might be able to help."

Daphne sighed. "Fine. We still need to die tonight-"

"Daph-neee." Astoria's tone grew reproachful again.

"-but now I want to know something first," Daphne continued, ignoring her sister. "So I'll trade you an explanation for an explanation."

Harry shrugged. "Deal. So what's going on?"

"Our parents have always been sort of tacit supporters of He-Who-Must-Not-Be-Showering," Daphne said, "but now that he's back, he wants a lot more than that. And with the decline of our patron House Black, our commercial interests aren't paying us enough to satisfy him. Instead, our parents decided to offer me as a "wife" to Fenrir Greyback to save their own skins. I probably wouldn't last a month from his 'attentions' and wouldn't really want to, anyway, so I decided to take the quick way out. Astoria is even more fragile than I am and would be next on the list if I died, so I stupefied her and took her with me."

"Holy shit!" Harry nearly dropped his wand. "That may be the worst thing I've ever heard and I've had a fucking terrible year so far. Isn't there anything Professor Dumbledore could do to help?"

"I already asked him," Daphne said. "Wizarding law gives our parents absolute authority over our marriage contracts. If we tried to refuse, the contract could be used to torture us into compliance." She laughed harshly. "Look at you, Potter, trying to be a hero and give us some sort of happy ending. That's just for children's stories. Go ahead, save our lives and go to bed satisfied with your heroism. Let thoughts of my screams on my wedding night sing you to sleep."

Astoria shook her head. "That's mean, Daffy. He's just trying to help. I know he would if he could, and it's not his fault if he can't somehow overturn magical law in the two days we have left. He's doing his best to save us."

"Merlin's pants, Potter," Daphne said. "You see this? This is what happened when she read of your exploits here when she was younger. You got her hopes up, got her sorted away from me into Gryffindor, and now I have to be the one to disappoint her. So fuck you very much, too."

"Daph-ne," Astoria reproached her again.

And once again Daphne ignored her. "Anyway, that's my story. Your turn, Potter. How the hell did you prevent me from cursing you just now?"

"You tried to curse him?" Astoria smacked her on the arm. "That's awful!"

"I told you," Harry said, "I have no idea. I didn't even realize you were cursing me until you started speaking it, and I was just going for a Protego."

"Then how the hell did you zap me? I felt like someone hit my hand with bubotuber pus as I spoke. Only cursing my parents should cause a reaction like that...or maybe their patron, I guess. But you're a Potter, not a Black."

Lovely. Just the memories Harry wanted to dredge up right now. "Sirius Black was my godfather, and the closest thing I've had to a father since Voldemort killed mine when I was a baby."

"What." Somehow, a single word conveyed the idea that Harry Potter had fond feelings for Sirius Black was the most mind-numbingly stupid thing Daphne had dealt with so far that day, a day that included planning her own murder-suicide.

Harry sighed. "He was framed for the murders. Peter Pettigrew is still alive and is the one who betrayed my parents. Sirius spent all those years in Azkaban for a crime he didn't commit, and then he died last summer saving me from Bellatrix Lestrange. He loved me, and I got him killed."

Wordlessly, Astoria walked over and hugged Harry. He didn't flinch so much from physical contact anymore, and it was hard to think about flinching from someone as small and cuddly as the second-year Astoria. And while he didn't think he really deserved hugs anymore, he couldn't imagine explaining that to Astoria, much less that she would agree with him. So he hugged her back, and just for a moment the world stopped grinding him under its heel.

Daphne broke the spell, and when she spoke Harry noticed that she was somehow sitting down now. "Harry, I need to ask you a very important question." Her voice wavered as she spoke. "Did Sirius have any house elves?"

"Yes, one named Kreacher," he said, releasing Astoria.

"Call him."

"What?"

"Just call him right now."

He shrugged. "Kreacher?"

The house elf appeared with a small pop. "Yes, master whose mixed blood shames House Black?"

Harry looked to Daphne for assistance with that question, but even in the moonlight he could see she'd gone pale and was unlikely to be much help. "Um...nothing, Kreacher. Please go home now."

Kreacher grumbled and popped away.

"Dumbledore told me I'd inherited the house," Harry said by way of explanation. "Is that what's going on?"

"No," Daphne said. Her voice was hollow now. "Tori, try to hit Harry with a curse. Any curse. Doesn't matter."

She shook her head. "I won't hurt him."

"Please."

Something raw in her voice forced Harry to speak up. "It's OK, Astoria. You can go ahead."

Astoria screwed up her face. "Slugulu-ouch!" She turned to Daphne. "That hurt! What happened?"

"The same thing that happened to me when I tried, and what would have happened to him if he'd tried to counter-curse me instead of shielding. I'm glad I didn't use an Unforgiveable or I'd probably have been Squib-ified, to say nothing of losing our home." Daphne rose to her feet as she spoke, her voice becoming firmer with each word. "Tori, did you hear what he said about his real relationship with Sirius? If Sirius loved him like a son, then he probably gave him more than just the manor. Potter, were you at the reading of Sirius Black's will?"

"No," Harry said. "Dumbledore told me about it afterward, but he said some parts had to be kept secret for various reasons."

"That man." Daphne shook her head. "You didn't just inherit the house, Harry. You inherited the House."

Somehow her capital letter came through in her tone. "You mean...?"

Daphne curtseyed again, sincerely this time. "My Lord Black."

Harry shook his head. "You have got to be kidding me."

Tori's eyes widened and she did likewise. "My Lord."

"Please stop," Harry said.

"My lord, I need to ask of you a favor." Daphne's voice wavered and she no longer looked him in the eyes.

"OK, this is just creepy." Harry rubbed his temples. "I don't believe I'm asking this, but could you go back to insulting me? I feel more comfortable with that than whatever this..." he gestured vaguely in Daphne's direction, "is."

"Would you stop playing dumb?" Daphne hissed. "This is hard enough as-is, and if Tori's life weren't at stake, too, I'd just head back up the tower rather than abase myself like this. Yes, I insulted you, and now I need your help. Just keep rubbing it in. What do you want me to do, kiss your feet?"

"What the hell...no! No foot-kissing!" Harry had no idea what was going on, but at least he knew his stance on foot-kissing. That was some weird shit right there, regardless of what Lee Jordan said.

"He was raised by muggles," Astoria said, her voice so quiet the night breeze threatened to steal the words away. "He doesn't know."

"Could someone tell me what I don't know, please?" He paused. "Wait, did you say I could help?"

"Yes," Daphne said through gritted teeth. "Listen carefully, Potter. I want you to picture the biggest Pureblooded prat you can possibly imagine: fat, self-satisfied, and wearing robes worth more than the Weasleys' whole house probably is. Got that? Congratulations, you've now met Sirius's grandfather, Arcturus Black. Going by the man I've met in his portrait-"

That statement threw Harry for a loop until he remembered the portraits at Grimmauld Place. After all these years, he still wasn't quite used to the Wizarding World.

"He was an unmitigated ass of the old-school variety," continued Daphne. "Do you know how people like that saw women? As property, Potter; just another family asset to be bought and traded." Starlight glittered in sapphire as she finally looked back into his eyes. "And we can use that."

"What...what do you mean?" Harry's mouth had gone inexplicably dry.

"Under the old ways, being a patron house had even more advantages than it does now," Daphne said. "A patron would have the right of first refusal on any brides from subordinate houses. It's a disgusting tradition, one that any decent house would long since have ended. But, like I said, Arcturus was a fucking prat. So I'd give better than even odds that you can marry me right now, Potter. And once that's done, I can use another old tradition to claim Tori as my handmaiden for a year and protect her, too."

Harry blinked. "Wait, you want me to marry you?"

"That is indeed what I said. I'm not asking for a lifelong commitment here, just long enough to ensure neither Tori nor I can be married off to that monster instead. Then you can divorce me and go court Granger or Weasley...or the other Weasley for all I care."

Astoria smacked her on the arm again. "That is the least romantic proposal I have ever heard of."

"We'll make sure your eventual fiancé does something romantic, then," Daphne said. "I'm just trying to ensure we both live long enough to see that."

"Are we even old enough to get married?" Harry asked. "I don't turn seventeen until next summer."

"Normally, no," Daphne said, "but the Purebloods who wrote the laws gave themselves some weasel room in case they wanted to empower a younger Heir and prevent their own House from being temporarily taken over by someone else. Because Sirius Black has apparently made you the Lord Black without appointing a guardian, and because you were over fifteen at the time he died, that power all goes straight to you. You can marry, control the family funds, the hereditary Wizengamot seat, everything."

"You're serious," Harry said, trying not to think about the other responsibilities she'd casually mentioned in that list and instead focus on the most pressing problem. "There's no other way out of this for you?"

"Of course I'm serious! I just tried to murder my own fucking sister, Potter." Her voice cracked, but she had it under control again before Harry's brain could even process what had happened. "If there was another way, don't you think Dumbledore or I would have lunged at it? Hell, I'd even squib-ify the two of us if it meant we'd be safe, but marriage contracts and other vows work on squibs, too."

"But, I mean, I can't just marry you, can I?" Harry asked.

Daphne shrugged. "Technically, the ritual just needs two willing participants and a witness capable of bearing a wand. So, yes, you can. The question is whether you will. I can't make you and you don't owe it to us. However, if you don't want to, I'm taking my sister back upstairs to finish what I started and I won't let you get in my way again. I don't care if the Patronage Oath burns my damned fingers off, you will either help me or get out of my way. Is that clear?"

"I won't let you hurt him." Astoria placed herself between Daphne and Harry. "He's just trying to do what's right. It's not his fault nothing's right anymore."

Harry sighed. "That pretty much sums it up, doesn't it? Sirius is dead, Voldemort is back, my friends are mad at me, Daphne is trying to kill herself, and now I have to get married to someone who just tried to hex me. Sure, why not? The last time I did something this stupid, I got someone killed. Maybe this time it'll work out better, and at least if I get you killed you're no worse off than you would have been if I hadn't been here tonight." As he spoke, he realized he would probably get someone else killed with this maneuver, too: Daphne's parents. Dumbledore would want him to try to convince them to do the right thing and convince them to back off, but as far as he was concerned, her parents could burn. He was tired of risking others' lives to give monsters in human form yet another chance at redemption.

Daphne sighed. "You don't have to sound so enthusiastic about it."

"Yay." Harry waved his arms in the air. "Someone who doesn't even like me has been coerced into marrying me. Yay. I will have so much fun being aggressively ignored by you for the rest of the year. Whee."

Astoria laughed. "It's so much fun watching you be on the receiving end of that for once, Daphne!"

"I can't ignore you, Potter," Daphne spit out. "The marriage would have to be consummated as soon as possible to ensure my parents couldn't annul it and marry me off anyway."

"Oh." Harry realized he'd been right to worry about his night getting weirder. "I...um...oh, Merlin, I'm so sorry. I didn't know. I won't touch you any more than minimally necessary to consummate the marriage, I promise. This...isn't right."

"It's not your fault, Potter," Daphne said. Astoria took her hand as she spoke, which seemed to help her calm down a bit.

Daphne took a deep breath and held out her wand. "No sense putting it off," she said. "Touch your wand to mine and repeat after me."

Harry nodded and did so.

"I, Daphne Greengrass."

"I, D...Harry-"

"Damn it, Potter!"

Astoria giggled.

"Sorry," Harry said.

Daphne gritted her teeth. "Fine. Let's try this again. I, Daphne Greengrass."

"I, Harry Potter."

"Being of sound mind and magic."

"Being of sound mind and magic."

"Do bind myself to Harry Potter."

"Do bind myself to Daphne Greengrass."

"Before the assembled witness and magic itself."

"Before the assembled witness and magic itself."

"Until parted by death."

"Until parted by death."

Tendrils of golden light snaked out from the tips of their wands and wrapped themselves around their hands and wrists. Astoria placed the tip of her wand on theirs and added, "I, Astoria Greengrass, witness this union."

With that, more tendrils of gold burst forth and wrapped her small hand, as well, and all of the tendrils glowed even more brightly before gently fading away into the night.

"That was beautiful," Astoria whispered.

"Yeah," Daphne said in a subdued tone, "it kind of was."

Harry nodded.

"Daphne?" Astoria asked.

"Yeah?"

The younger girl squealed and glomped Harry with a huge hug. "I've got a big brother now and he's awesome!"

Harry staggered back two steps under the unexpected onslaught. "I guess you do," he said. Some instinct he didn't know he had told him to ruffle her hair, so he did. She hugged him even tighter.

Daphne sighed again. "Tori, you're making this even more awkward and that is not a low bar."

Tori's giggle was muffled a bit because her face was buried in Harry's robe. "Don't care. 'M keepin' 'im."

"You see what I have to put up with?" Daphne asked. "Come on, Potter. Let's get her to bed and get on with things. Think you can get us back inside without getting caught?"

Harry extracted himself from Tori's hug and pulled out a piece of parchment. "Only if," he said, "we solemnly swear we are up to no good."

Tori's gasp as the Marauders' Map sprang to life was possibly the cutest thing he'd ever heard, and even Daphne was struck dumb for a moment. "Damn, Potter," she finally said. "Just...damn."

Harry grinned and, in the dim light, he swore he saw a stag lean over from the edge of the map and kneel its front legs slightly, as if taking a bow.