[Sometimes, Yuuna becomes a little sister]
Fuu: Itsuki, what would you like for tonight's dinner?
Itsuki: Hmm, we had curry until last night...
Fuu: Let's go with curry udon, then!
Itsuki: Let's choose something other than curry.
Yuuna: stare
Fuu: Let's go with something in season like saury then. Then, it may a bit too early for it to be in season, some stew.
Itsuki: I think I want stew more than fish...
Fuu: Okay, let's go with stew then. I'll go buy some ingredients before going home, so you go on ahead.
Itsuki: Okay.
Yuuna: stare
Tougou: What's wrong, Yuuna-chan? You've been staring at Fuu-senpai and Itsuki...
Yuuna: Ah, Tougou-san! I was actually observing both of them.
Fuu: Observing us? Hehe? You wanted to burn the intimacy of Shikoku's number one "girl power sisters" into your eyes?
Karin: "Girl Power Sisters" is something I can't see. Your intimacy is the real deal, though.
Sonoko: Yuyu, did something happen?
Yuuna: Recently, I got a request from the theatre club, and I ended up helping them out...
Tougou: Now that you mention it, they put in a request because they were short on hands.
Yuuna: Yeah. I thought I'd help out with props or scene-shifting, but I ended up with a role...
Tougou: I'll be coming to watch, Yuuna-chan.
Yuuna: Thank you, Tougou-san. So, my part is the protagonist's little sister...
Yuuna: But since I've had never had any siblings or sisters, so I thought I'd observe Fuu-senpai and Itsuki-chan since they're the ones familiar to me.
Sonoko: You're pretty serious about this, Yuyu.
Yuuna: So, Itsuki-chan! How does it feel like to be a little sister?
Itsuki: Ehh... erm... now that you ask me how it feels... I've been born as a little sister so it's pretty difficult to explain.
Karin: Little sister, eh? In the first place, there aren't may siblings or sisters that are close like Fuu and Itsuki.
Yuuna: Oh, you're a little sister too, Karin! Want to share your experience?
Yuuna: stare
Karin: S-Stop that!
Tougou: I-I'm not a little sister, so I can't be of any use to you, huh...
Yuuna: That's not true! Besides, you're more like an "older sister", Tougou-san. You give off a very mature aura.
Tougou: I'm Yuuna-chan's "older sister"!
Fuu: Nobody said that, though...
Sonoko: That reminds me: in the past, we had a game where Mino-san was the little sister and Wasshi was the older sister...
Sonoko: An idea! That's right, Yuyu. Rather than just observing, how about "real-life epxerience"? That way, I think you'll be able to understand the little sister role better.
Yuuna: "Real-life experience"?
Sonoko: Yes! From those of us with experience, let's choose who Yuyu will spend her day with as their little sister!
Tougou: Yuuna-chan will...
Karin: become a little sister?
Sonoko: For starters, try calling me "onee-chan". CALL ME "ONEE-CHAN", MY SISTER!
Yuuna: Erm... Sonoko-oneechan.
Sonoko: More, like a spoiled child!
Yuuna: Onee-chan!
Sonoko: Like a naughty, boyish little sister!
Yuuna: Y-Yo, big sis!
Sonoko: Like a diligent little sister!
Yuuna: Um, my dear elder sister, is this acceptable?
Sonoko: YES! Like this, Yuuna-chan will live like a little sister among those who have experience. That way, won't she understand a little sister's feelings?
Tougou: Yuuna-chan will become a little sister...
Yuuna: Mimori-oneechan, Mimori-oneechan!
Tougou: What's wrong, Yuuna?
Yuuna: I saw a scary movie, and now I can't sleep alone... Can we sleep together for tonight?
Tougou: Fufu, you're so easily scared, Yuuna. Sure thing.
Yuuna: Waai! Hooray!
Tougou: That's a great idea...
Karin: Yuuna... will become a little sister...
Karin: Overhead slash! Lower slash! Yaaa!
Yuuna: Karin-oneechan, Karin-oneechan!
Karin: What's wrong, Yuuna? Your older sister is training right now.
Yuuna: Yeah! That's why I thought that we should train together! I want to be the Perfect Hero like you!
Karin: Hm, the path ahead is rough. Will you still tread it?
Yuuna: Yeah! As long as I'm with Onee-chan, I'll do my best no matter what the training!
Karin: Not a bad idea...
Tougou: Ahem. I think that "Yuuna-chan's One-Day Little Sister Plan" is a great idea.
Tougou: But if she's going to act as a little sister, I believe that an older sister is needed. If nobody minds, shall I take the role?
Karin: No no no, I'm fine with that role, too.
Sonoko: Fuumin-senpai gets to be the older sister!
Fuu: Eh, me?!
Sonoko: That's because you're the one and only "Real Onee-san" among the Hero Club. Rather than anyone else, I think it would be better for s natural one to fill the role.
Karin: Muuu... I can't deny that.
Tougou: If it's Fuu-senpai... I have no choice but to withdraw...
Yuuna: So I'll become Fuu-senpai's little sister! Looks like it's going to be fun!
Sonoko: Right, right. Not only at school. Today you'll stay at her house and take your time with your little sister experience.
Fuu: Well, if you think of this as part of club activities, then I have no reason to disagree. I'm fine with it.
Fuu: If you're staying, make sure you tell your parents first, okay?
Yuuna: Okay!
Itsuki: B-But...
Sonoko: Don't worry. Don't worry, Ittsun. It's just for a day. You don't need to worry that your sister will be taken away from you, beacuse Fuumin-senpai's will always hold you as her most important one.
Itsuki: I-It's not like I had those worries...
Sonoko: By the way, if Yuyu is going to spend the night at Fuumin-senpai's, then how about staying at another place for the night, Ittsun?
The next day…
Yuuna: (And so, from this morning to the next, for 24 hours, I will be Fuu-senpai's little sister.)
Yuuna: A little sister's first day starts with going to school together!
Fuu: Yuuna, did you bring everything that you need for today?
Yuuna: I'm all right! ...is not right. If I'm her little sister, I shouldn't use formal language.
Yuuna: I'm okay, Fuu-oneechan! I properly check what I need to bring every morning.
Fuu: I don't think I'll get used to you calling me "Onee-chan", Yuuna.
Yuuna: Ahaha... me, too. But it's kind of refreshing and fun.
Fuu: Oh, Yuuna, move here. A car's coming.
Yuuna: Thank you, Onee-chan.
Fuu: It's dangerous, so make sure you stay on the sidewalk.
Itsuki: (On the other hand, I'll be Karin-san's sister for an entire day.)
Karin: For starters, we should go to school together, right?
Itsuki: Right...
Karin: Erm... also, you don't need to talk to me so formally.
Itsuki: Ah, you're... right, Karin-oneechan.
Karin: I can't get used to it... besides; I was technically a little sister back at home...
Itsuki: You're righ... yep.
Itsuki: Ah!
Karin: What's wrong?
Itsuki: I forgot to bring my English textbook!
Karin: Eh, really?! Can't be helped, let's go back and get it. I'll come along with you.
Itsuki: But if we go back now we might be late for school...
Karin: It’s fine, we'll make it if we run! Come one, let's go!
Itsuki: Okay!
Yuuna: Ah, Fuu-oneechan!
Fuu: Yuuna? What made you come up all the way to the third year classrooms?
Yuuna: Nothing, I was just passing by. By the way, a person from our class has a request for the Hero Club.
Fuu: Okay, make sure to bring it after class.
Yuuna: You got it, Onee-chan!
Yuuna: See you after school!
Fuu: Sure thing.
Girl Student: F-Fuu-chan... What’s with the "onee-chan"?! Since when was Yuuki-san your little sister?!
Fuu: Oh, no, that's not what it means... there's a story behind this, you see...
Girl Student: There's a complicated family situation, eh... All right, I won't ask any further!
Fuu: I think she's misunderstanding this...
After school…
Fuu: Today's Hero Club activities ends here! Take care on your way home, girls.
Yuuna: Okay!
Fuu: Umm, you're staying at my place tonight right, Yuuna?
Yuuna: You're ri... yup, Onee-chan! Because we're sisters.
Fuu: Let's go home together, then. I'm going to buy some things from the supermarket, you coming with? Or do you want to go home?
Yuuna: I'll come with!
Tougou: ...Yuuna-chan... I wonder what this is... it's like a wide hole is opening in my heart...
Sonoko: You'll be going home with me, Wasshi!
Tougou: Sonocchi...
Sonoko: Let's get some gelato along the way.
Tougou: Sure, lets.
Karin: Itsuki will be staying at my place, right? Let's go home?
Itsuki: Sure, Karin-oneechan.
Itsuki: Fufu. I think calling you Onee-chan is pretty fun.
Karin: I think I'm already used to me being called that, too.
Yuuna: Onee-chan, I'll help you prepare dinner.
Fuu: I'm fine, I'm fine. You can go watch some TV.
Yuuna: Ah... sure.
Fuu: By the way, Yuuna. Is there anything you don't like to eat?
Fuu: If there's anything, I'll cook something that doesn't use those.
Yuuna: I wonder if she always treats Itsuki like this? Itsuki is really loved.
Yuuna: Time to eat!
Yuuna: Mmmm... Delicious! Fuu onee-chan, you're really good at cooking!
Fuu: That's because of the King of Girl Power who's personally in charge of the Inubouzaki kitchen!
Fuu: Ah, you won't be able to reach this dish, right? I'll go get it for you.
Yuuna: Thanks, Onee-chan.
Fuu: I'll give you another helping of rice, too.
Yuuna: Mmmm... She’s so perfect... Amazing.
Yuuna: Thanks for the meal!
Yuuna: Onee-chan, let me help you tidy up and wash the dishes.
Fuu: Don't worry about such a thing. Let me do it. You can go rest, Yuuna.
Yuuna: Hmmm... I'll go heat the bath, then.
Fuu: I've already done it, so it's fine. Oh, you go ahead and take yours.
Yuuna: Eh?! You already made dinner and cleaned the dishes. Offering me to go first in the bath is...
Fuu: What are you saying? You're my little sister for today, right? A little sister isn't supposed to mind those small things.
Yuuna: So this is normal between Fuu-senpai and Itsuki-chan... Being Fuu-senpai's little sister is amazing!
Meanwhile, Miyoshi Karin and Inubouzaki Itsuki were...
Itsuki: Geh... Haaa... Fuuu....
Karin: Okay, running and 100 thrusts, done!
Itsuki: W-Why do I need to... haa, haa... take the same training as Karin-oneechan?
Karin: Itsuki. Your training here will surely be useful in the future. Believe in your big sister!
Itsuki: Y-Yeah!
Karin: Your high power output and judgment are really amazing. But since you're not used to exercise, so I think your stamina is lacking.
Karin: Stamina comes through continuous training! Continuation is power.
Itsuki: Haa... Fuu... Yeees.
Itsuki: Being Karin-san's little sister is pretty hard...
Karin: We'll have dinner after training. If you don't get your nutrients, you won't become strong, after all.
Karin: Our dinner is a pork cutlet bento! Dried sardines! Vitamin supplements! Amino acid supplements! Dried sardines!
Itsuki: That does look pretty packed with nutrients...
Yuuna: I'm done with my bath.
Fuu: Yuuna. I've prepared your textbooks and notebooks for tomorrow so you won't forget them.
Yuuna: Eh?! You went that far?!
Fuu: Eh? Isn't that normal?
Fuu: Whenever I leave it up to Itsuki, she always forgets something.
Yuuna: (S-She's too perfect.)
Fuu: Also, I've prepared the bed so you can sleep whenever you want to.
Fuu: She fell asleep in this room once and I had to carry her all the way to her bed.
Yuuna: Something like that happened...
Fuu: Ah, but you're not like that, huh...
Yuuna: (Fuu-senpai looks a little lonely!)
Yuuna: (But... it's so amazing to be her little sister... Even if I don't do anything and sit here, everything gets prepared!)
Yuuna: (It's like a king or nobility!)
Fuu: Hm? What's wrong, Yuuna?
Yuuna: Nah, it's nothing, Onee-chan!
Yuuna: ...Ah.
Fuu: What is it?
Yuuna: Aaaah! I forgot to do today's homework! There's a lot for math, too...
Fuu: It can't be helped. I'll tutor you so work on it here.
Yuuna: Eh, but you need to prepare for your exams...
Fuu: My little sister's studies are more important. Don't be so reserved, you're my little sister.
Fuu: This is around the part where you use systems of equations, eh? The trick behind systems of equations is to write the problem itself as such.
Yuuna: Okay... like this, and this... you're right, it's done!
Fuu: Right? Of course, I'm a third year so I should be able to at least teach second year math.
Yuuna: Ahh... it's amazing. This life where you entrust almost everything to Fuu-senpai...
Yuuna: It makes you want to be her little sister forever... but if I get too used to this, I feel like I won't be able to go back... it scares me a bit.
Yuuna: And this finishes... the last problem... I'm already... sleepy...
Yuuna: zzz... zzz...
Fuu: Ara, she fell asleep, eh? I guess I'll carry her.
Fuu: Hup... she's heavier than Itsuki, but a lot lighter than I expected.
Fuu: She looks like she can handle herself, but she's definitely still a child.
Fuu: Yuuna is very considerate. She always acts lively, but the truth is she observes everything around her and thinks of others more than anyone else.
Fuu: Compared to her body, her heart is very mature.
Yuuna: zzz... Fuu-oneechan... munya... I'll help... mn...
Fuu: Geez, looking out for others even in your dreams, eh? You don't need to worry about that.
Fuu: You can put yourself at ease. You can let other people spoil you, Yuuna.
Yuuna: ...Fuu-oneechan...
Fuu: I don't have to hold her hand much unlike Itsuki, but in her own way, Yuuna looks like she can also be a handful as a little sister.
Yuuna: (The next morning, the One-Day Little Sister Experience was over)
Sonoko: How was it, Yuyu? What were your thoughts on being Fuumin-senpai's little sister?
Yuuna: It was amazing!
Tougou: A-Amazing?! W-What was?!
Yuuna: It felt, really perfect!
Fuu: Really? Isn't that normal?
Itsuki: I have muscle pain today.
Karin: It's fine. Muscle pain is proof that your body is strengthening.
Karin: I'll give you some citric acid supplements. It should help with the muscle pain.
Itsuki: Yes. Thank you very much...
Yuuna: I was almost at the point where I wanted to really be Fuu-senpai's little sister and live together with her.
Fuu: You're welcome anytime, Yuuna.
Both: Eh?!
Itsuki: No, no! Even if it's Yuuna-san, I won't give up my position as Onee-chan's little sister!
Tougou: That's right! Living together is...
Tougou: (I even wanted Yuuna-chan to become my little sister!)
Yuuna: Ahahaha, I was just kidding.
Fuu: True, my hands are already full with Itsuki alone.
Itsuki: Uuuu... I'm not that much of a handful... I think.
Yuuna: That afternoon, I was able to perform the little sister at the play. Thank you, Fuu-oneechan!