Izuku considered herself a very rational girl. Her father, Toshinori, was a renowned scientist. As a single father, he had taken control of her education. He'd raised her to understand the laws of the universe, such as the need to go to bed on time in order to wake up refreshed the next morning and the importance of a balanced nutritious diet. Izuku took pride in her logic, even if her elementary school classmates called her a know-it-all (particularly the loud and annoying Katsuki Bakugo.) In Izuku's world, everything could be explained by logic and science.

Thus, when Izuku spotted a white-furred, red-eyed rabbit wearing a waistcoat and holding a pocket watch, she immediately said, "You shouldn't exist."

The rabbit ignored her and muttered, "I'm late. What should I do? Sensei goes buggy when I'm even a little late."

Izuku stomped her foot on the ground. "Are you ignoring me? Rude!" She had come to the riverbank to observe the wildlife, making sketches in her notebook that she planned to later show her father. She did not appreciate being disregarded by the local wildlife, especially some bizarre talking creature who should not exist. "I could excuse the red eyes as albinism, but a rabbit with a watch is simply illogical. How could a rabbit talk? You shouldn't have the right vocal cords, much less the intelligence. I must be hallucinating or dreaming. It's the only scientifically viable conclusion."

The exceptionally impolite rabbit continued to treat her as if she didn't exist. He moaned, "I shouldn't have stayed up so late last night playing League of Legends. I was so close to reaching Grandmaster tier."

A gamer rabbit? This was only getting even more ridiculous. Izuku said, "I don't feel like I'm in a dream, but people who are dreaming often don't. I don't remember falling asleep either, but I haven't ingested any hallucinogenics, so a dream remains the more likely conclusion. Dad wouldn't approve if I took drugs." She peered down at the rabbit. "You're probably the subconscious manifestation of my desire to wake up from this dream and get back to drawing."

Finally, the rabbit looked up with a growl, red eyes meeting her green ones. He shoved her. "You're in my way, NPC." Then he ran off.

"You are very rude rabbit indeed!" Izuku shouted after him. Her shoulder stung where his paw had made contact. It was only a very mild pain, but it still felt a bit too real for a dream. Toshinori would no doubt tell her that a true scientist would never ignore evidence even if it didn't fit with her hypothesis. Also, if she could capture a talking rabbit, then she'd become world famous and make Katsuki regret ever mocking her. Driven by curiosity and ambition, Izuku chased after the rabbit.

The rabbit squirmed into an unusually large rabbit hole, suiting his stature as an oddly large woodland creature. There was enough room for a young girl, too. Izuku followed him down.

Immediately, Izuku plummeted into total darkness. As the wind whipped through her hair, she rapidly regretted her reckless (and perhaps even illogical!) choice to go chasing after a strange lagomorph. Her father would be disappointed in her for not even preparing climbing equipment first.

The darkness and falling continued for so long that Izuku realized, "Oh, this must be a dream after all." If she'd actually gone down a rabbit hole, she would have surely hit the bottom by now. What strangeness had caused her dream to last this long? Perhaps she'd failed to properly digest her breakfast and it had given her nightmares? This was very boring. "Something interesting had better happen in my dream soon, or I'll wake up!"

It had been an empty threat, her having no control over her state of consciousness, and the fall continued for a while until Izuku landed on a pillow shaped like a giant mouth.

"What an illogical design for a pillow," she grumbled as she sat up. "It's hardly comforting to feel like one has fallen into an open mouth. I would like to complain to whoever designed this place." She looked around. She appeared to be in a cave without much else besides the pillow. How strange, who had put down the pillow then?

"Nice to meet you. My name is Himiko Toga," a small voice said. Izuku looked up to see a vampire bat clinging upside-down to the ceiling. The bat had two blond buns of hair. Flashing fangs, she asked, "Want to be friends?"

"Bats are not supposed to have hair," Izuku said. Then she realized she had been rude. Toshinori always said that manners and kindness were even more important than logic. "But your buns look lovely. Sure, we can be friends." Izuku wasn't entirely certain about a talking bat friend but felt the need to make up for her blunder. "I'm looking for a white rabbit, have you seen him?"

"That's Tomura," Toga said. "He ought to be at the royal garden party, but he just passed by here, so he must be late. All for One will be annoyed! Now that we're friends, you can eat me."

Izuku gaped at this non-sequitur. "Excuse me? I don't eat my friends. In any case, I'm not convinced that bats are edible. You might have a funny disease."

"If you won't eat me, then I'll drink you!" Toga pounced, sinking her fangs into Izuku's hand too fast to be stopped.

To Izuku's astonishment, she shrank down in size until she was about the same height as the bat. Her transformation let her break free from the fangs. She ran blindly, determined to get away from what appeared to be a vampire bat with very illogical powers. Toga shouted after her, "See you later!"

There was a crack in the cave wall. Izuku ran through it, emerging into the sunshine. A forest spread around her, the grass as tall as trees and the actual trees impossibly giant.

"Oh, whatever should I do?" Izuku asked herself in despair. "Dad will be very upset if I return home as small as his hand. The scientific community will be baffled. And I don't even want to think about how Kacchan will mock me for it."

Laughter came from above her. "You look like you've had an encounter with Toga." A gecko lizard sat on a mushroom and smoked a hookah. "I'm Spinner, and—ack!" He choked. "Ugh, Tomura told me that smoking was cool, but it tastes awful."

Sagely, Izuku said, "My father says that smoking tobacco will give you lung cancer."

"Actually, I'm smoking the delusion that destroying everything will somehow create a better society."

Izuku tapped her chin, pondering. "I've never heard of that drug before."

"It's not even making me feel high, just depressed."

"Then you should stop taking it."

"Good idea." Spinner tossed away his hookah. "Here's a tip in return. If you eat from the right side of my mushroom, you'll grow larger again. The left side makes you smaller, if for some reason you want that."

"What's the logic behind that?" Izuku asked suspiciously.

Spinner shrugged. "I dunno."

Izuku shifted from foot to foot. She hated things that did not have rational explanations, but she also hated being tiny. Toshinori would probably tell her that scientists learned through conducting experiments. Darting forward, she tried a bite of mushroom.

The change happened so fast Izuku nearly fell over. Her arms pinwheeled as she grew. "Thank you!" she cried at the gecko below her. As she reached her full height, Spinner became small. He waved at her and said something too faint for her to hear.

For lack of any better ideas, Izuku walked down the forest path. "At least the forest seems normal now," she muttered. "No rabbits wearing clothing or talking lizards—"

"Meow," came from above. To be clear, this was not the sound that a cat makes. It sounded like a sarcastic young man speaking "Meow" out loud.

If Izuku believed in superstition, then she would have thought she'd jinxed herself. She looked up. A scraggly, scrawny cat perched on a branch. He had black fur with patches of purple, dead skin between the stitch marks. Droopy blue eyes regarded her with amusement.

"Do you require medical attention?" Izuku asked, because her father had taught her to be kind to animals, even very ugly ones.

"I'm not the one in trouble, brat. You are." The cat snorted, another oddly human sound. "The name's Dabi."

"I'm Izuku." She stopped herself before saying her family name, because Toshinori said not to give her full name to strangers.

"You don't look like you come from these parts, little Izuku."

Izuku admitted, "I chased a rabbit down a hole. Everything's been very illogical since then. I keep shrinking and growing." Tears threatened to fall from her eyes, but she barely restrained them. "Please, do you know which way I should go?"

"That depends on where you want to go," Dabi said with, in Izuku's opinion, unnecessary smugness.

She stomped her foot on the ground. "I would like to meet humans, not more talking animals! A human might have a cell phone to call my father. None of you make any sense! I don't even understand how you are communicating with feline vocal cords."

Dabi gestured down the path. "Yoichi lives that way. He's as close as gets to human around here, although he's quite mad."

"But a madman doesn't sound useful in helping me get home," Izuku said, a note of whine entering her voice in spite of herself. In her defense, it had been a long day.

"Oh, you can't help that." Dabi laughed. "We're all mad here. I'm mad. You're mad. My entire family is rabidly insane, especially my father."

"I am not mad!" Izuku cried. "My teachers and my father all praise me for my rationality and good grades."

"You must be, or you wouldn't have ended up here," Dabi said.

Izuku refused to accept this. She took great pride in her intelligence. "Can you prove only mad people are capable of traveling down rabbit holes? Do you have any peer-reviewed scientific studies on the topic? Maybe you just go around calling perfectly sane people mad."

Dabi sneered. "You can meet Yoichi and judge for yourself if he's mad."

"Hmm." Izuku had to admit this sounded like a solid scientific test. "But a sample size of one person is hardly conclusive evidence—"

Dabi burst into flames.

Izuku leapt away. "Stop that!" she wailed. "Spontaneous cat combustion is not logical!"

But the cat ignored her, burning away until only his grin remained hanging in the air. It was unbearably creepy. Izuku quickly walked away.

For lack of any other ideas, Izuku continued down the path. She soon reached a cat-shaped home with pointed white ears for a chimney and a roof thatched with fur. "Oh, dear, this house does look mad." She started to wonder if she should have gone somewhere, anywhere else.

A long table covered by a white cloth sat in the lawn, with nine thrones around it. A pretty white-haired young man with cat ears sat at the head of the table, pouring tea. At least this individual looked mostly human, except for his ears and tail. To his right sat a man with spiky red hair and floppy basset hound ears. To his left was a blue-haired man with Border Collie ears. Izuku felt reasonably confident in her guess about the breed of dog, since she had studied and drawn many types in her notebook. "Are any of you Yoichi?" she called.

The cat-eared man looked up. "Yes, I'm Yoichi. These two are Second and Third."

Second rolled his eyes. "Stop calling us all by numbers. I'm Kudou. Who voted you as First anyway?"

"I'm Bruce, and I'm not changing my name even if you don't like it," Third said.

Focusing on Yoichi, Izuku said, "A cat told me that you're mad. Would you care to confirm or deny this claim?"

Yoichi reared up, affronted. His tail shot out straight. "My big brother is mad! I'm the sane one in the family."

Although Izuku would like to believe it, she had been taught to trust the evidence. "Hmm, but having nine plates laid out for three people seems a tad mad."

"We have four other friends," Kudou said. "They're coming by to join us later."

"That doesn't explain the extra two plates," Bruce whispered.

"Those are for unexpected guests." Yoichi grabbed Izuku's arm and yanked her over. "Come, sit, have tea." He placed a headband with rabbit ears on her head. "There, now you fit in with the rest of us."

As the green ears flopped over her forehead, Izuku sighed. It appeared the irritating Dabi cat had probably been telling the truth. Yoichi seemed only partly human, and definitely on the wrong side of sanity.

Yoichi poured her a cup of tea, while Bruce flopped onto the table and went to sleep. His head rested on his empty plate. It seemed rude to Izuku, but in her experience adults didn't like it when she corrected their manners.

Since Izuku had experienced very bad luck with eating and drinking in this strange place, and she did not want to turn into anything else, she did not touch the tea. Instead, she asked, "Do you know how I can get home?" It seemed unlikely, but worth a try.

Yoichi stroked his chin. "Maybe the real home was the friends you met along the way."

"I'm not sure I'd call them friends," Izuku said. "At best acquaintances." Even Toga had gotten her friend status removed for biting.

Kudou cleared his throat. "If you stay here too long then you stay forever, but if you leave fast enough then you'll be safe."

Despite knowing it was an illogical emotion, Izuku felt panic rising up from her chest. "How long is too long?"

Yoichi pulled out a basket full of heart-shaped tarts and put one on each plate. "I don't know, time doesn't move here." He gestured at a grandfather clock behind him, sitting outdoors for some strange reason, with the minute, second, and hour hands all frozen perfectly at six o'clock.

"Just because the clock is frozen doesn't mean time is frozen." Izuku wondered if she could trust anything these madmen said. She hoped not, because she didn't want to be stuck in this unscientific place forever.

Kudou said, "Time doesn't work here because Yoichi attempted to murder time. And also his brother."

"Can you blame me? He's very annoying," Yoichi hissed at Izuku.

"Time is annoying or your brother is annoying?" Izuku asked.

"Both!" Yoichi cried.

Kudou sighed deeply. "Yoichi's brother is the most annoying being in existence. But Yoichi, I wish you'd left time alone. Now it's teatime forever." He nudged the sleeping Bruce. "Wake up, it's tea time."

"It's always tea time," Bruce mumbled. "Let me go back to sleep." He put his hands over his head.

The entire forest shook. A trumpet bellowed. Someone shouted, "Make way for the King and Queen of Hearts! King All for One and Queen Inko!"

All for One swept forward wearing a majestic red robe, with Inko on his arm in a puffy red dress. Their crowns both had a heart-shaped ruby in the center. Unlike his brother, All for One did not have cat ears, leaving Izuku confused about if Yoichi's ears were real or fake. Though who knew if genetics applied in this place without any natural laws? The royal couple were surrounded by a guard of what appeared to be playing cards walking on stubby white legs.

Izuku gasped. Of all the strange things she'd seen in this place, playing cards come to life must be the oddest. She could perhaps excuse the talking animals as genetically modified. Her shrinking and growing could have been advanced technology. But how could these playing cards be alive? They were too flat to have space for organs. Their scrawny limbs did not seem to have any muscles to use to move. One of them must have announced the King and Queen, yet they had no voice boxes or mouths. This was an outrageous assault on rationality!

Next to her, Bruce snored. Izuku wished she could also fall asleep and hopefully dream of a more logical place. What a strange reversal, when reality became madder than dreams!

Sweeping up to the table, All for One cried, "Little brother, you're a thief. Tomura told me that you snatched my tarts while he was playing video games."

Izuku sweated. She realized that with a tart sitting on her plate, she must look like an accomplice.

Yoichi examined his claw-like nails. "You can't prove anything."

Next to him, Kudou bit into his tart. "Yum, this is delicious."

"I know." Yoichi devoured his tart in nearly a single bite. His mouth full, he said, "Food stolen from my brother tastes the best."

Kudou laughed. "It reminds me of the time I stole you from All for One."

"So romantic." Yoichi blew a kiss at Kudou, then turned to All for One. "There are no tarts here. You're falsely accusing me." He still had crumbs all over his face. Izuku sank downward, wondering if she could hide under the table. Yoichi was definitely not the more sane brother, no matter what he claimed.

Turning to Inko, Kudou asked, "Would you like a tart?"

"Why, yes, thank you." Inko took a seat at the table. Kudou served her a tart. She ate as watched the brothers bicker.

All for One cried, "You're a younger sibling, and they are all thieves."

"You're an older sibling, and they are all liars by nature," Yoichi retorted.

All for One waved his arms. "I have indisputable proof. The brother thief has spiky hair." He pointed his royal scepter at Kudou. "Therefore he must have stolen the tarts. Off with his head!"

"Stop!" Izuku screamed, leaping up and standing on her chair. She had been compelled to come out of hiding not by justice, but because of the sheer illogic of the situation. No longer could her scientist's mind accept the insanity around her. "This is ridiculous! Yes, Yoichi and Kudou clearly stole the tarts. There's so much evidence. The tarts are sitting on the table, Yoichi has crumbs on his face, and they both confessed. But you can't convict Kudou because of his hairstyle. How much hair gel he uses has nothing to do with this situation. That's merely your prejudice. This is the stupidest trial I've ever heard of in my entire life!"

"How dare you insult me?" All for One bellowed. "Off with her head!"

The cards had been advancing on Kudou, but they turned to attack Izuku instead. For a brief moment, she felt afraid. Then she realized she could easily knock away the cards. They were as flimsy and frail as a piece of paper. In short order, she'd tossed away a dozen of them.

Face red, All for One screamed, "More guards! Overwhelm her!"

Izuku straightened her back and raised her fists. In addition to science, Toshinori had also trained her in martial arts. Yoichi and Kudou applauded her performance. Frankly, she would have preferred if they'd been useful and helped her fight instead.

"That's my Ninth!" Yoichi shouted. "Or are we on Eighth? I lost track."

Bruce had fallen over in his slumber and leaned against Inko. She gently pushed him away and wrapped her cloak around his shoulders. Her gentle gaze fell on Izuku. In a sweet voice, she called, "Darling, that's only a little girl, you can't kill her."

"I'm certain I can," All for One said. "With enough cards, we'll eventually be able to knock her down. My guards are entirely expendable. In an absolute pinch, if I had to lower myself to attack her personally, I'm much bigger than her. I could strangle her with one hand."

That did seem to be true. Izuku gulped. This wouldn't be the first time her temper and desire for justice got her into trouble. Her gaze went frantically to Inko, the beautiful and kind queen, seeking mercy.

Inko stood up and grabbed her husband's arm. "Absolutely not! I forbid you from killing such an adorable little girl."

Izuku breathed a sigh of relief.

Blissfully, Inko continued, "I've always wanted a daughter. I'm going to adopt her."

Izuku nearly fell off her chair. Queen Inko was just as mad as the rest of them!

All for One peered at Izuku. "Hmm. At a closer look, she does have the most adorable rabbit ears." He patted Izuku's head. Squawking, Izuku tried to bat his hand away, but moved too late. Beaming down at his wife, All for One said, "Queen of my heart, you always have the most wonderful ideas. From now on, this girl will be our daughter."

"Presenting the new princess of hearts!" the playing cards bellowed, lining up in two rows. They were battered but appeared undaunted.

Izuku's head spun. Everything had gotten out of control too fast. "Wait!" she cried. "I want to go home."

Inko smiled. "Of course, we'll take you back to the royal palace at once. I can't wait to decorate your room and pick out your adorable dresses."

"No, I want to return to my real home with my father." Tears pricked Izuku's eyes. She bitterly regretted ever chasing that silly rabbit.

"Big brother, you're a monster! You can't adopt her against her will!" Yoichi cried. "Because I saw her first. If anyone's adopting her, then it's me and my hero."

Kudou nodded. "We need an extra two people to fill up our tea table."

"But I already have a father…" Izuku said despairingly.

"Bring him, too," Kudou offered. "Then we'll be nine in number. Perfect!"

"I've always liked the number nine," Yoichi said. "It's agreed."

"I didn't agree!" Izuku protested.

All for One screamed, "Trying to steal my daughter in addition to my brother? Off with his spiky head!"

The cards marshalled for war. Yoichi and Kudou flashed their claws. Izuku considered running away, but All for One was looming behind her. "You can't adopt me without my father's permission," she cried, on the verge of tears, one last attempt to reason with them and apply the laws of her world.

Together, Yoichi and All for One said, "I'm your father."

In a mad panic, Izuku decided to try the one thing she'd never contemplated, the only thing people here understood, a horribly wicked tactic: illogic. She shouted, "If you're both my father, then you need each other's permission to adopt me. Then neither of you can adopt me!"

Yoichi's face fell. "Oh, no, she's right."

All for One grabbed his brother by the front of his shirt and shook him. "This is all your fault, you fool! You and your stupid thief. Because of you, I can't give my beloved wife the daughter that she desires."

"If you can't adopt me then I should get to go home," Izuku said, trying not to beg.

The world spun. Many bright colors flashed in front of Izuku's eyes. When she could see again, her real father's face loomed over her.

Smiling, Toshinori said, "You fell asleep on the river bank. Time to go home."

"Oh!" Izuku sprang to her feet and hugged her father.

He patted her on the back. "What brought this on? You're clinging to me like you're afraid of losing me."

"I'm just glad to see you," Izuku mumbled into his shoulder. "I had the most peculiar dream."

"You'll have to tell me all about it," Toshinori said with a chuckle.

Back home, sitting at the dining room table and eating tarts, Izuku poured out the whole long story.

When she'd finished, Toshinori threw back his head and laughed. "A wild dream indeed! It sounds like it would make a fun book."

"As I thought all along, it was a nightmare caused by failing to properly digest my breakfast," Izuku said serenely, delighted to finally have a rational explanation for everything. "I'm glad such illogical creatures don't exist."

The mirror hanging over the mantle glowed, and for a brief instant, two white-haired brothers appeared peeking out from the other side. Then they were gone, leaving only a shimmering light on the surface of the looking glass.

OMAKE TIME!

Izuku: There's a logical explanation for everything I'm experiencing. For example, what if I've been abducted by aliens?

Tomura: Do aliens like video games? I love video games.

Izuku: You can't even manipulate a controller with your paws!

#

Izuku: Thank you for restoring my height.

Spinner: Stop shouting, you're deafening me.

Izuku: I'll never forget this kindness:

Spinner: As I lose my hearing, I'm regressing back toward hating everything.

#

Izuku: Dabi was right about Yoichi being mad.

Dabi: I've been summoned by vindication.

Izuku: I thought you burned away into only a grin.

Dabi: Spontaneous combustion killed the cat, and satisfaction brought him back.

#

Kudou: I rescued Yoichi from a vault in this universe too.

Yoichi: I'd locked myself in while sweeping. But it's the thought that counts.

All for One: Sure, you "accidentally" locked yourself in. You had a lot of accidents while living with me.

#

Izuku: You two brothers are a lot alike.

Yoichi: Take that back!

All for One: Treason!

Izuku: You are both selfish and silly creatures attempting to adopt me against my will. Therefore, logically, you resemble each other.

Yoichi: Oh, if you're only using logic, then I can just ignore it. I don't see the point of logic. I believe what I want to believe.

All for One: Logic has been banned in my kingdom.

Izuku: See? You're agreeing with each other again!

Author's Note: I wrote this story for Jumble June, an event where authors swap AUs. It was loads of fun writing for Sofjoy82's Princess of Hearts fic. Delete the spaces to get the link to the fic that inspired this one:
archiveofourown.
org/
works/37373626/chapters/93262732