AO3 LINK: http://archiveofourown.org/works/2487854/chapters/5520515
The first time he ever lied, Mikoto Mikoshiba had been all of eight years old.
"Aw, c'mon, Mikorin." The dark-haired girl had said back then, pulling at his wrist so he couldn't go away. "Just this once?"
"First of all: no." The redheaded boy had all but spat out, trying to wrench himself free of his sister's grip with admirable force. "Second of all: Yu, would you please stop calling me 'Mikorin'?"
"Nah. If I did, then what choice would I have left to use when referring to my precious little brother?" Yu drawled, pulling on said precious brother so they now lay side-by-side on the fluffy bed.
"Call me 'Mikoto', at least. That's my actual name, yanno." Mikoto huffed, sitting up, swatting at his sister's fingers - which were attempting to tickle the hell out of him. He then crossed his arms and tried very much to pull the disappointed face their dad would always pull when they did things like keep the cookie jars in their closet or stay up late sharing ghost stories well after their bedtime. As Mikoto happens to have their father's coloring and their mother's fine-boned features, however...
"See, that right there! You'd make a perfect heroine, Mikorin!"
"Thank you - wait, what part exactly are you gonna make me go as here? I thought you were the prince, Yu? And like hell am I gonna be the heroine!"
"Aw, too bad, you would've been cute in the dress," Yu whined, her mouth in a frankly endearing pout. "Cuter than Chicchan, even."
"Tsch - fine, whatever, okay? I'll go." Mikoto sighed, knowing even then that no matter what he does, he'll never be immune to his sister's puppy-dog eyes. "But why am I wearing this wig again?"
"Like I said - your hair obviously screams 'Mikoshiba'." Yu had said, sitting up to fix the wig on tighter over her brother's head. "Just like our dad and grandpa and great-grandpa and too many forefathers to count. And after all the effort I've done so Senpai could only know me as 'Kashima' - if he knew I was related to the Mikoshiba heir, my cover would be blown, I'd lose all my friends, Senpai would hate me, and my life would be but an empty shell of what it had become -!!"
"You're overreacting."
"I'm telling the truth! Believe me, Mikorin, you don't know how things could get out there."
And she was right - Mikoto didn't. Where Yu had pleaded and cajoled their parents to have her go to grade school as "Kashima" - their mother's surname, still reasonably wealthy but not as eye-catching as their legal, billion-dollar-worth Mikoshiba - Mikoto had to be cajoled, in turn, just so he could turn up to his daily tutorials. Where Yu thrived on the applause and attention of her peers (of some unnamed "senpai" of hers, in particular), Mikoto lived for his alone time, for the hours he spent holed up in his and Yu's shared room playing video games, tending to their balcony garden, reading the fairytale romance novels Yu kept leaving behind.
"Then why do I have to go and do this thing anyway?"
"...because I'm your big sister, and you love me?"
"I don't."
"Aw, you wound me, darling," Yu had said, pressing a hand to her heart in mock-agony. "And not just because you say such ill words, but because you didn't even make an effort at lying."
"Eugh, whatever."
"Anyway, seeing as I've got this and all, it doesn't seem like I've got a choice," Yu sighed, nodding towards the gigantic cast obscuring one of her pale, long legs.
She had just told Mikoto and their parents that she had just 'fallen off a box', which, considering her somewhat-flighty nature, had yet to set off any alarm bells. But the truth was, Yu had wandered off a little too off stage while watching her senpai perform - something no one needs to know, least of all Senpai himself. The look on Senpai's face when he had seen Yu in the cast had been a picture-perfect look of pure anguish, and Yu would've applauded at the sight had he not looked so close to tears.
(Said tears were scrubbed up angrily, covered up with a handkerchief as he ran hurriedly out her hospital room, and were almost gone by the time he had shoved a package of baby castella into Yu's surprised face.)
(Yu's favorite food has been baby castella ever since.)
"Can't you just, I dunno, get someone else to fill in for you? Like, say, your mysterious, beloved 'Senpai', if he's so good an actor?"
"...Senpai isn't mysterious."
Had Mikoto been a couple years older, he would've had the foresight to say something about how his elder sister did not do anything to protest again the notion of this Senpai being Yu's 'beloved'. But he isn't, so he lets this slide clean over his head without a second look. He'll eventually end up regretting it later.
"You know Senpai can't play this role either. He tried, of course, as soon as this happened, but - well, Chicchan's his little sister. Having on-screen romantic chemistry with your real-life, actual little sister would be weird."
"Anyone else, then? Anyone else who is, I dunno, not the girl's brother, who isn't me?" Mikoto blurted out, wringing his hands, seemingly grasping for straws. "Any other guys from your class?"
"Well...I did try asking Nozaki -"
"Nozaki? As in Mayu-kun's brother?"
"Yep, that's the one! But he said something I can't understand about working better unseen, and Senpai said his acting was as exciting as 'watching paint peel'..."
"Harsh."
"True, though. Anyway, Nozaki already wrote the play to begin with, so he doesn't want to be any more involved in the play as he already is. No one else in my class stands out though, I'm afraid." Yu mused, looking up at her brother with a curious expression. "I think you should take it, Mikorin."
"But there'll be...people. And cameras and stuff." Mikoto said, drawing his legs into his chest and sinking his face into his knees. "I can't do this, Yu. I'm sorry. I keep thinking I can, but...I can't. I really can't , and I'm sorry."
Yu takes one look at her brother and his quivering self, his scrunched up eyes, his cheeks lit up by an embarrassed flush, and decides to tuck his cute little super-worried self into the curve of her arm. "Hey, Mikorin. You wanna know what the best thing about acting is?"
"What, making a fool outta yourself in front of people?"
"No, silly," Yu croons, pressing a kiss to her little brother's hair. "It's the chance to be someone other than who you really are. To be able to live out someone else's life. Isn't that what you always do in your favorite video games anyway? Living out an alternate life?"
"..."
"Also, I promise to treat you to burgers after."
"Yeah, fine, okay, I'll do it. Go start from that line again."
"Yessir, Mikorin sir."
==
The first thing Mikoto thinks when he sees his co-star for the first time is 'crap, she's hella cute'.
