01. boyish girl and gal girl came here! Rei Rei Hi, hello! It's summer vacation, and you're playing games at home? Yuu. Ah, there you are. It's been a while. How have you been? You've grown quite tall. [Rei] It's been so long since I've been in this room. It's starting to look a bit like a boy's room. [YU] When I came here before, there were still robot toys lying around. It's completely changed. [Rei] ...... What? Who are you guys? ...... Don't tell me you've forgotten about us! I took care of you when you were in diapers... I used to play with you so much? I'm sorry... I'm Yu... I'm Yu, right? How can you forget me after not seeing me for a few years? You used to call me "Rei-sis" and "Yu-sis". Rei... This blonde? Ah ...... I see. When I met you, it was before I became like this. [Yuu] Ha-ha-ha!　It's true that Rei may have changed too much compared to the past. She's a blonde gal now. Compared to Rei, I don't think I've changed that much, couldn't you tell? Rei. Yu used to be almost like a boy. You used to wear shorts and a hat. You wouldn't even recognize me if you saw how much bigger I am now. [Yu] I wonder if that's true. I doubt that. Anyway, have you figured it out by now? If you still don't believe me, I'll tell you all kinds of embarrassing stories about your past. ...... [Rei] You already believe me, don't you? ...... So, what are we doing here? Well, you know... Yuu. Actually, we ran into your mother outside. She told us that you've been rebellious lately, and that you're in a lot of trouble. She says you don't study and play video games all the time. [Rei] That's why. If it's only during the summer vacation, I'll help you with your studies! I said to Auntie. Auntie, go and ask her right away. Yu! So we're your tutors from now on. We're so smart, you know? [Rei] You can't tell us to go home... I'm so sad, Sis... You used to be so cute, but you've become so cocky... Ah!　Yu!　Catch me! [Yuu] Yes, I got you. Sorry. Your mother also asked me not to let you go. [Rei] Don't be so rude~! Yuu, I'll put you down on the bed! Yuu. Yes, yes, that's it! Rei! You can't resist now, can you~! We'll hug you from both sides to stop you from moving... The killer, big sister sandwich! Yuu... Phew... ...... He's even stronger than before... ...You're still a handsome boy, aren't you? But I guess I've become a little cocky... [Rei] Come on, Yuu? We have to teach him a lesson, don't we? We have to make him the handsome, obedient, cute little brother he used to be. [Yu] Right, Rei. That's right, Rei. It would be sad if he turns out to be a bad boy. We have to make him a good boy ♡♡.