A/N: The story itself is a dark little tale that came from my diseased imagination.

WARNING: A/U. Rated M for Incest, although no actual lemons (yet). Bart and Lisa are teenagers. Don't like, don't read. Partially inspired by the novel Forbidden, by Tabitha Suzuma.

Have the Simpsons Ever Been Normal?

"Leese…"

Bart took a deep breath as Lisa looked up and fixed him with her bitter stare. Her left eye was swollen shut, already tinged with purple. The corner of her mouth was bloody, most of the blood trickling from a split lip.

"I broke up with Patrick, Bart. Happy?"

"Hell to the fuck no!" Bart snarled. "I'm gonna rip off his nuts and stuff them down his throat!"

"Don't bother. He's going back to Boston tomorrow."

"I don't give a shit! I'll kick his ass at the airport!"

Lisa smiled and then winced; smiling hurt her mouth. "How about getting me an icepack instead?"

Bart stood for a moment, framed in the doorway of her room, and then Lisa heard his footsteps heading downstairs.

He stomped into the kitchen and yanked open the freezer. The ice trays were empty, as usual. Cursing, Bart headed directly for the basement and Homer's beer cooler. Two six-packs of Duff were floating in a sea of half-melted ice. Bart scooped as many whole cubes into a plastic bag as he could. The only other option was a squashed package of frozen peas that Bart had last seen under his father's ample rear end.

When he got back upstairs, Lisa still had not turned on her light. She was sitting on her bed gazing at the floor. Even in the dim light, Bart could see tears trickling down her face and the sight hit him like a kick in the stomach. It wasn't that he'd never seen Lisa cry before; he had just never seen her like this. Defeated. Broken.

Bart brought the ice pack. Ignoring her squeak of protest, he placed it gently against her bruised face. "Don't, Leese. He's not worth it."

"I did my best" Lisa whimpered. "Mom always said if you gave up trying to change someone for the better, then you were just a quitter. I worked so hard!"

"I know. I know you did." He didn't, actually. Lisa was extremely close-mouthed about her relationships, but he knew that once she loved someone, her love was total. She was like Marge that way. Bart let her take the pack and sat down beside her. "But remember, Mom has to believe certain things in order to stay married to Dad. You don't."

"I know!" she said with a choked sob. "That's just it! I feel so stupid! How could I let that happen to meeeee….!" Her words trailed away into a howl of pure misery.

Mindful of her injuries, Bart gently wrapped his arms around her. Lisa froze for a moment, startled, before relaxing into the embrace. "I think he reminded you of Colin" Bart went on, sounding honest-to-God thoughtful for what had to be the first time in his life. "Same accent, same interest in the causes you go for. Same passion about his beliefs that you have about yours. Same adorable naïve optimism—OW!" Bart grinned as Lisa's small fist whacked him in the chest.

"He didn't remind me of Colin" Lisa mumbled.

"No? Huh. How about Bono? Or Ed Begley Jr.? He has those wired-rimmed glasses and I'm pretty sure he's gonna go bald before he hits 21."

"So are you" Lisa reached up and rubbed a hand through Bart's spiky blond hair, which was already starting to recede. She gave a watery giggle.

"Hey! Quit it!" Bart grabbed her hand and laced his fingers through hers. Lisa sighed and leaned back so she could look into his face. "He reminded me of you."

"Me? Thanks a lot!"

"No, he did!" Lisa insisted. "I never told anyone, because Mom would have insisted that I stop seeing him, but Patrick did a ton of stuff that wasn't exactly legal. He's the one who released all those spotted owls into Springfield forest; he's the "Junkyard Shooter" that Chief Wiggum was trying to catch-the one who kept shooting rock salt at the nuclear plant workers who were trying to dump toxic waste. And he's the one who sent those blackmail letters to Mr. Burns!"

"Really? I thought that was you. Patrick doesn't know how to use compound sentences."

Lisa laughed out loud, flinching at the pain in her mouth. "Well, I helped of course. But he's the one who went ahead and sent them. Seriously he was like you, Bart. Resourceful, brave…he thought anything was possible if you had enough nerve. You're like that."

"And this attracts you?" Bart joked, trying to ignore the warmth flooding his face. "I would think after all these years you'd know better. I'm never going to amount to anything."

"Don't say that! Don't you ever say that!" Lisa whacked him again. She glared at him, furious. "I don't care what the teachers say! You're smart. You just don't apply yourself because Dad taught us to always take the easy way out. Look what it's gotten him! 20 years in the nuclear plant without a single promotion, constant debt, and a drinking problem! His life didn't have to be like that and neither does yours. You said I don't have to believe the same things Mom does. Well, you don't have to believe the same things as Dad either!"

Bart couldn't help smiling. "But Dad does have one thing right: he knows Mom is the most precious thing in his life. No other person in the world would have faith in him the like does. And the guy who gets you is gonna be the luckiest asshole on the planet, because you're just the same way."

"Oh Bart!" Lisa snuggled closer. "I have no idea what's come over you, but I'm going to enjoy it while it lasts."

Bart didn't answer. He knew what had come over him, and he was pretty sure it was against every law of man, nature and God. A little sister was to play tricks on; a little sister was someone to defend from bullies (provided one knew about the bullies) ; a little sister was someone to tease and torment, advise and encourage, but a little sister was NOT someone to fall in love with. Even when you're nineteen and she's seventeen. Even when you can't imagine any other girl being as much a part of you as she is.

Maybe the habit of rule-breaking was too strong in him. Wrong or not, Bart loved Lisa to the depths of his soul. Not that he'd ever tell her, of course. It was completely sick and perverted and even if it wasn't, Bart knew that Lisa deserved a smart, successful guy—one who was guaranteed to go as far in life as she would. Bart was not that guy. It worried him that she was already developing a Marge-like habit of fussing about his grades, his appearance, and his plans for the future. Hate to break it to you, Leese, but I'm more like Dad than you think. I love Springfield. I love our family. I don't want to waste four more years going to some school far away when I'm not even smart. I'm going to stay here and work and look after Mom and Dad and Maggie.

"Bart?"

"Mm?"

"You're squeezing."

He let her go. "Sorry."

"I didn't say you had to stop. Just not so tight, okay?"

Bart prayed that the light in the room was dim enough that she couldn't make out the blush spreading across his face as he gathered her close once more. Lisa sighed happily and nestled against him. One of her fingertips traced lightly over his arm. Just that one delicate touch made his skin tingle and burn. He cleared his throat.

"I thought Patrick would care for me the way you do" Lisa said softly. "I thought that would make it right."

"Make what right?" Bart whispered, before mentally kicking himself to Shelbyville and back. His heart was pounding like a jackhammer. He had the sudden wild urge to tell her to shut up, to not destroy this moment and leave their bond undisturbed.

"How I feel" Lisa looked up at him, her good eye bright and shiny with tears. "Bart, don't you know? Haven't you guessed?"

Bart shook his head and tried to remind himself to breathe.

Lisa shifted so their faces were level. Bart closed his eyes and nearly groaned aloud as her soft, abused lips touched his own. "Lisa…"

"I know!" she murmured. "I know it's wrong! Of course it is, but I can't help it! I love you, Bart Simpson. I love you that way—the way a woman loves a man. I don't know how or why! I just know the guilt's eating me alive. I'm a freak, Bart!" She bowed her head and began to sob again.

"Lisa...Leese...please..." Bart tugged at her hands. "If you're a freak then so am I." He gave her a little shake. "You hear me? So am I."

Lisa raised her head, her blue eyes shocked and disbelieving. Bart nodded. "It's true. I'm a 100% grade-A freak. And I love you too. That way. The way a man loves a woman."

When she didn't reply, he leaned closer and whispered, "Have the Simpsons ever been normal?" A dizzy, over-energized feeling was zinging through his bloodstream. Feather-light, he kissed her cheeks, her eyelids, and finally her mouth, his heart slamming hard into his ribcage when she opened to him. She tasted so good! Like cinnamon and honey. Like home. He cradled her face in both hands, never wanting the kiss to end. Unfortunately, however, they both needed to breathe. When he raised his head, Lisa wound her arms around his neck. "I'm scared, Bart."

"So am I."

"Mom and Dad can never find out. It would kill them."

"I know. Mom especially."

"So what do we do?"

"We take it slow" Bart said seriously. "Reallyslow. You're still underage, and you're going to college in another year. I'm going to stay here and start at Springfield Vocational Trades." Lisa opened her mouth to protest and Bart placed his hand over it. He continued, "If this is just some sort of temporary insanity, then it should die out while we're separated. I don't think it will. In fact for me, I know it won't. But you deserve a shot at the good life Lisa, and I won't hold you back."

"But SVT!" she shook her head at him. "Bart, you're smart enough for college! You could come with me! There's no need for either of us to stay in Springfield. We could start a whole new life, somewhere nobody knows us."

"Lisa, I don't want college. I never did. I can learn a trade at SVT. My auto-shop teacher says I'm a natural. And somebody needs to be here to take care of Mom and Dad and Maggie. You know that sooner or later, Dad's gonna wind up on disability with the way he eats. And Mom hasn't held a job in forever. There will need to be money coming in. And in a few more years, Maggie will be off to college too. What do you think will happen then?"

Lisa was silent. After a moment, she nodded reluctantly. "Okay. I hate to admit it, but you're right."

Bart grinned. "Happens more often than you might think. Shove over."

Lisa let go of him and scooted to the far side of the bed. Bart stretched out and gently tugged her down beside him. "All of that's for the future. Right now, we have almost 24 hours before Mom and Dad get home. Let's make the most of them."

Cuddling into her brother's embrace once again, Lisa felt the tension, sadness, and overwhelming feelings of self-loathing drain slowly from her body, leaving her exhausted. She pressed her ear against Bart's chest and lulled by the steady beat of his heart, soon drifted to sleep. Bart kissed the top of her head, smiling at the way her unruly hair curled up to tickle his nose. Her soft curves in his arms felt like everything he ever wanted. Worry was for later. Right now, he had it all.