Author's Notes: Written for Lady Phoenix Fire Rose's Pairing One Hour Challenge/Hardest Challenge Ever with the pairing Regulus/Lily and the prompts "Let me go" and "lonely".

Also for my Hogwarts is Home hh_sugarquill Bingo Card with the prompt "A fic set in Diagon Alley", and to celebrate the opening of lily_and_black, a Lily/Any member of the Black family community on Livejournal.

Lily/Sirius and Lily/Regulus – enjoy!

)O(

When Regulus had been young, he had become so used to resenting his brother that it became second nature to him to dislike everything that Sirius cared for. If Sirius expressed interest in a class at Hogwarts, Regulus would immediately loathe the class and stop trying in it. If Sirius mentioned wanting a Quidditch team to win, Regulus would instantly decry it, telling him that the team was useless and worthless and would never win. And if Sirius so much as glanced at a girl with any sort of interest, Regulus would immediately give her a critical glare and later tell Sirius in detail about all the flaws that made her physically disgusting.

Or, rather, that was what Regulus liked to do.

There were occasions, however, when he could find nothing to insult about a girl that Sirius was interested. It was a rarity, but it was the case when, while Sirius and Regulus were out getting their school books in Diagon Alley, a girl came up to Sirius with a wide smile on her face.

"It's been ages," she said, draping her arms around Sirius's shoulders and hugging him tightly and Regulus automatically ran his eyes up and down her body.

She was very pretty.

It was dreadfully difficult for Regulus to admit that even for a second, and even more difficult given the way she was draping herself over his brother. This wasn't a girl who Sirius was just looking at – this was a girl who obviously liked Sirius a great deal.

Regulus scanned her carefully for qualities to insult. He might have criticised the fact that she was just a little too curvy, with wide hips and a rounded stomach that pulled slightly against her blouse, but the build was attractive, if anything, and he knew full well that if he tried to say that she was fat, Sirius would counter with reference to her breasts or her backside…

Eugh.

Her hair, bright red, was dishevelled, but irritatingly prettily so. It was nicely tousled and shifted softly over her shoulders. And she had lovely eyes – so vibrantly green…

Regulus blinked, realizing that she had noticed him staring at her. His cheeks coloured slightly as Sirius looked over to him and rolled his eyes.

"Lily," he said, indicating Regulus, "that's my brother, Regulus. Regulus, Lily."

"I didn't know you had a girlfriend," Regulus said petulantly. A small smile played on Sirius's lips, but the girl – Lily – looked rather shocked. She dropped her arms from around Sirius's shoulders immediately.

"I'm not his girlfriend," she said, shaking her head. "We're just friends. He wouldn't have a Mudblood for a girlfriend anyhow," she added, forcing a laugh. Sirius slapped her lightly on the arm.

"Don't say that. It's not true."

"Mudblood?" Regulus wrinkled his nose. "You're a Mudblood?"

"Shut up," Sirius told him and Lily laughed a bit, covering her mouth with her hand.

"We're just friends," she repeated.

"Are we?" Sirius assumed a mock pout and reached out, putting his hand on Lily's hip. Her cheeks went bright pink, but she didn't push him away and Sirius moved his hand a little lower, squeezing her lightly. "Friends with benefits, though, yes?"

"Shut up, Sirius," she told him, and she blushed rather prettily.

"I didn't know that most people who were just friends acted like that…" Regulus looked pointedly at Sirius's hands, and he flushed, taking a step forward so he loomed over his younger brother. Regulus had to snicker – Sirius was anything but intimidating.

"You just shut your mouth," he snarled, obviously trying very hard to sound menacing but managing only irritation. "It's none of your business what Lily and I do–"

"You are doing something, then?" Regulus asked innocently.

"Just leave it." Lily grabbed Sirius's arm and pulled him back. "It's not worth it, for God's sake, really… let him think whatever he wants. It's not like James would believe him if he decided to go tell him that you and I were together – which we're not, you little brat," she added sharply, glancing at Regulus before he could say a word.

"Your friend, James?" Regulus challenged his brother. "So she's his girlfriend? You're running around with your best friend's girlfriend? God…" He sneered. "I thought you were supposed to be the good one."

"Come on." Lily grabbed Sirius's arm and dragged him away from Regulus.

"Mother and Father'll have a fit if I leave him alone," Sirius said, pausing, and Regulus felt a little swell of pride. Maybe his brother wasn't completely useless after all – maybe he actually did care more about his brother and what his parents thought than he did about that slag.

Though it was difficult for Regulus to think of her as a slag, if he was honest. He was still transfixed by her bright eyes and hair and her very ample chest. He swallowed.

"He's not going to tell anyone." Lily glared at Regulus sharply. "You're not, are you?"

Yes. I'm going to tell Mother and Father that Sirius was supposed to be helping me find my books and he decided to run off and shag you against an alley wall or whatever you two are going to get up to…

But Regulus kept his mouth shut. He bit down on his lips and tongue until he tasted blood, then forced himself to shake his head very slowly and jerkily. Lily nodded decisively, then took Sirius's arm again and led him away.

What a bitch.

Regulus fumed quietly, then, glancing quickly over his shoulders to be sure that no one who knew him and might want to talk to him was around, followed Lily and Sirius quickly. Lily's bright hair stood out in the crowd, for which he was grateful – it made it so much easier to find them again if he lost sight of them. Sirius was striding along at her side and unless Regulus was very much mistaken, the two of them were deeply engrossed in conversation. He tried to strain his ears enough to pick up a few words, but the street was too crowded, there was too much space between them and there were too many other people talking for him to be able to catch even a word.

Sirius and Lily rounded a corner into a back alley, and Regulus felt a little swell of derisive satisfaction. Ha. They were going to do it – wait until Mother and Father hear about this…

He slipped to the side of the street and peered around the corner, just in time to see the couple disappearing around another bend. He followed them slowly, tentatively, going as quietly as he could when the bustle of the street died away, then poked his head around the corner and looked down the alley at them.

Sirius had Lily pressed up against the wall and she was kissing him feverishly. Her hands were tangled in his hair and one leg was wrapped around his waist and Regulus thought that his brother would surely kill him if he ever found out that Regulus was watching this.

Sick.

It was so sick, Sirius doing this with a Mudblood – Regulus had known that his brother didn't have proper Pureblood pride, but pressing a Mudblood up against a wall and kissing her like that – how could a Black ever lower himself to that?

Regulus pressed himself tightly to the wall, ready to spring back and away from the scene if there was ever even the slightest suggestion that Sirius might look at him. He seemed, however, far more interested in undoing the buttons of Lily's shirt.

"Stop it…" Lily murmured while Sirius pulled on the buttons.

"Mm?" His hands stilled and Regulus held his breath.

"I said… stop it." Lily pushed his hand away, covering the line of cleavage that Sirius had exposed. "Let me go, come on… I don't want to…"

Sirius let out a frustrated groan. "God, Evans…"

"Get off," she said firmly, and Sirius relinquished his grip on her reluctantly. "I've got shopping to do. And my mum and dad will be looking for me."

"Fine…" Sirius stepped back and wiped perspiration from his brow. "You are such a tease, Evans."

"You love it," she said, smirking slightly, and Sirius grinned.

"Yeah, I do." He kissed her quickly, then turned away from her, heading towards Regulus. He barely had time to dive behind a rubbish bin before he was seen, and he held his breath, chest heaving, until his brother's footsteps died away.

"You can come out now."

Lily's voice was dry and sardonic and Regulus held his breath, hoping to God that she wasn't talking to him. He didn't know who else she could be talking to, but he was sure that he would die of embarrassment if she caught him after he had been spying on her and his brother.

"Come on." He could hear the clicking of her shoes against the pavement, then she leaned over the bin and looked at him. "Come out. You're useless at hiding, you know."

Regulus coloured. "I- I wasn't–"

"Oh, please. I saw you. You were spying on your brother and me. That's a bit sick, really."

"Sick?" Regulus's mouth twisted as if he had just taken a bite of something sour. "It is not sick – I wasn't- enjoying it!"

"If you weren't enjoying it, you would have left." Lily extended a hand and helped Regulus up. "Get up, now – it's not as though I'm angry at you for it."

"You're- not?" Regulus looked at her warily. He couldn't think of any reason that she wouldn't be angry – after all, he had been spying on her while she was in a very compromising position and he knew beyond the shadow of a doubt that her and Sirius were… involved. Surely that was enough to be angry at…

"It'd be pretty stupid of me to start shouting at you now, wouldn't it?" Lily asked. Her voice was calm and reasonable. "If I got angry at you, it wouldn't exactly make you forget what you saw."

"Uh- that's- that's true…" Regulus stammered. He had no idea what to make of her.

"You seemed very… interested," she said, arching one eyebrow. "You like watching your brother with girls?"

"NO!" The thought revolted Regulus and he shook his head vehemently. "Nothing like that! God, why would you even think- I'm not- not like that!"

"Dear God, calm down." Lily rolled her eyes. "All right… so do you just like watching anyone? Voyeur?"

"No!"

"So why were you watching? And don't pretend it was morbid curiosity or whatever shit you're about to say," she added, before he even opened his mouth. "No one would ever watch their brother snogging a girl out of morbid curiosity."

"I did–"

"Don't lie," Lily told him sharply. "It's stupidly easy to tell that you're lying, you know, and it just makes you look like an idiot. So you go on and tell me right this minute why you were watching me and your brother."

Regulus felt as if his cheeks were on fire. He wanted to run away and never look back, never look at Lily and that infuriatingly smug expression on her face – or better, curl up into a ball and disappear right there.

"I was just…"

"Was it me?"

Regulus started a little at her bluntness. "Wh- what? N- no, of course- I didn't- I mean–"

"Oh my God, that's pathetic." Lily's lip curled. "You saw me and decided you'd fancy seeing me and your brother together… can't you find your own girl? Someone who you can snog instead of getting yourself off watching other people–"

"That's not what it was like!" Regulus clenched his hands into fists. "You must have a pretty damn high opinion of yourself if you think I'd want you that much so quickly – you're not that special, you know!" he added defiantly. "It's not like you're pretty."

"Good," Lily spat. "It's a good think that you don't think that, because I really don't fancy boys acting like I'm easy and that I won't mind them staring at me–"

"I don't want to stare at you!" he told her. "I don't want anything to do with you- I followed you two because Mother and Father told me to stay with Sirius and I didn't leave because I wanted to catch his eye and get him to stop. It's nothing to do with you!"

"Good," she said again, then turned and flounced away, and Regulus waited until she was gone before he sank to the ground shakily.

Every single word of that had been a lie.

His parents hadn't told him to stay with Sirius – they wouldn't have dreamed of entrusting him entirely to his lunatic of an older brother. They had told him to be careful and for Sirius to watch out for him, but they had all known that Sirius was going to leave him alone.

But that wasn't the biggest lie. It was a lie, yes, but hardly a serious one.

The real lie was when Regulus had said that he didn't want anything to do with Lily.

He would have had to be blind not to notice how attractive she was. Anyone could look at a girl like her – nice figure, good hair, gorgeous eyes – and say that she was attractive. It wasn't even an opinion, merely an observation.

It was, however, an opinion for Regulus to say that she was easily one of the prettiest girls he had seen and certainly the best looking by far of Sirius's constant stream of so-called girlfriends. Regulus was used to not even having to search to find flaws with them, but even with the most critical examination, he couldn't begin to think of even one thing to say that was unattractive about Lily.

Except, of course, that she was a Mudblood.

That was infuriating.

He swallowed hard, pressing his lips together, then drew in a deep breath and let it out slowly.

It was stupid of him to think about Lily at all. She was obviously interested in Sirius – and who could blame her, really? Sirius was, by all accounts, the handsome brother. He could have any girl he wanted falling over him in a second. And besides that, this Lily supposedly had a boyfriend…

And it didn't matter.

As much as Regulus tried to tell himself that what he was feeling was nothing but disgust for his brother for choosing to lower himself to the level of a Mudblood, but he knew that wasn't it. He had felt disgust before. This wasn't disgust.

It was jealousy.

Jealousy, because Regulus would have given almost anything in the whole world to have been the one that had pressed Lily up against the wall and kissed her and undone her blouse while her legs were wrapped around his waist.

It was jealousy coupled with the most profound loneliness, because he knew he'd never have her.

)O(

Fin