(A/N: So basically, Y/N's dialogue with this story will either be that she doesn't talk at all, and will choose to write in her journal, or she'll talk in a whisper/soft tone.)

-Iwatobi Swim Club-35 Days till Prefecturals-
"She's a natural!" Nagisa exclaimed excitedly as the four boys watched the (H/C) haired female jump from the diving board with anticipation.
Having borrowed a swimsuit from Gou, who was not too surprised at this point that the female didn't have one, Y/N was instantly put to practice by the young manager.
"Her style almost looks like Haru's." Makoto observed, rubbing his chin as if in thought as his green orbs widened in realization. "The only difference is she's swimming-"
Butterfly.
That's right, Y/N was swimming the Butterfly Stroke, a.k.a. the only stroke Rei can swim. And, as Makoto and Nagisa had described it, she looked like she was meant to swim that stroke, much like how Haru was meant to swim Freestyle. After all, there wasn't much of a difference from when she swam as a Mermaid, probably a reason why Author-Senpai calls it Mermaid Stroke instead.
"That was perfect Y/N-chan! Were you on a swim team before?!" Gou excitedly questioned. Y/N, who had just touched the wall and was stopping for a breather, simply shook her head no in reply.
"Your swimming style is very beautiful." Rei told Y/N, covering the lower half of his blushing face with his hand, causing Y/N's (E/C) hues to brighten.
"Arigato, Tako-kun." Y/N smiled happily at the male. (Tako: Octopus)
"T-Tako?" Rei blushed more at the random nickname, while some of the others laughed or looked amused.

___Quick Time Skip___
"Iruka-kun, Mako, I will catch up later." Y/N's declaration caused both makes to stare at her in surprise.
"Are you sure? Will you be able to find your way?" Makoto worriedly questioned.
Y/N smiled and nodded. "Hai."
"Are you ok with this Haru?!" Makoto asked, still seeming unsure of letting the female walk home alone. What if she got hurt? Or someone took her? What if she realized she didn't want to be with them at all anymore and ran away!?
Haru closed his locker and locked his blue eyes on Y/N's form, before shrugging his shoulders in his noncaring way. "She'll be fine. Just get home by curfew." He stated, patting Y/N's head before pulling Makoto out of the school building before he could begin to bicker in worry.
Y/N giggled softly, before going to find her target.
"Tako-kun!" Hearing the familiar female's soft tone, Rei looked up from his phone and curiously stared at the (H/C) as she rushed up to him.
"Y/N-San? Weren't you supposed to go home with Makoto-Senpai and Haru-Senpai?" Rei asked in curiosity.
Y/N smiled cheerfully, folding her hands behind her back as she nodded. "I told them to go ahead. I have a question." She told him. Seeing the look of confusion on the male's face, Y/N's cheeks burned up in embarassement. "I-I need help!" She exclaimed.
"Help with what?" Rei asked, now concerned at her odd behavior.
Y/N scratched her cheek with her index finger as she looked at the surrounding lockers. "I need help with learning. I don't understand." She stated.
"Oh." Rei looked relieved. "But me?"
Y/N sighed softly and pulled out the notebook Ms. Amakata had bought her. 'You're really smart!' Y/N pointed out the obvious. 'If anyone can help me, it would be you. Nothing would get done if it was Haru or Nagisa, Mako would be too nice, and Kou would be too stern.' Yet again pointing out the obvious through her written wording, Rei felt a bit proud that Y/N would think he'd be good at teaching and that she chose him.
"I'd be happy to help, but I-"
"I'll help you with your swimming!" Looking startled at being cut off, though he should be used to it by now with Nagisa, Rei stared at Y/N dumbstruck.
"I know you have trouble with certain...uh...strokes? I can help, if you can help me." Y/N continued, speaking the most since she's actually begun to speak.
Rei knew that his schedule was fully packed, especially with Finals coming up in a few months. Though, the thought of getting better at swimming other styles rather than just Butterfly was very tempting. Plus he'd be able to spend more time with this odd female.
"Rei-chan! Thank you for waiting!" Nagisa cheerfully called as he rushed in. "Oh, Y/N-chan, what're you doing here?" The blond beamed at the (H/C)
"Oh...uh..." Y/N glanced at Rei for some sort of help in explaining herself, and that's when Rei realized something.
She doesn't want the others to know she's having trouble! Once again feeling proud, or that was the only explanation he could come up with for the warm feeling in his chest, Rei sighed and began to pull Nagisa to the doorway. "Meet me tomorrow morning at the train station." He told Y/N, before he and Nagisa disappeared from the female's view.
Y/N smiled brightly, until she realized that he said morning. And tomorrow was a Saturday.

-Next Day-Iwatobi Train Station-34 Days Till Prefecturals-
Y/N sat crisscrossed on one of the benches at the station, doodling in the notebook she had been given as she waited for Rei to show up.
It was warm out, and no one was at the station which made it look almost abandoned. Her hair was pulled into a ponytail, and she wore one of Haru's T-shirts -a grey shirt that looked like a dress on her-, as well as a pair of black shorts, and a pair of Haru's old never-been-warn white sneakers.
Hearing the creaking noise of the train, Y/N perked up and stared at the oncoming vehicle. She stood up and put her notebook in her book bag, just as the doors to the train opened. She was suddenly surprised at the amount of people who came out of the train, practically shoving everyone out of their way.
Feeling someone harshly push her, Y/N stumbled back a bit, about to fall until someone had luckily caught her.
"Tako-kun!" She exclaimed in quiet excitement, causing him to smile wryly as a pink tinted his cheeks.
Rei held onto Y/N's wrist as he skillfully maneuvered the two off of the busy platform.
"Are you ok? You're not hurt, right?" The megane questioned in concern as he placed his hands on her shoulders.
"I'm fine, Tako-kun." Y/N grinned cheerfully.
Feeling his cheeks heat up, Rei glanced away from her in embarassement. "Let's just get going before Nagisa decides to show up." He stated, continuing to walk, her wrist still in his grasp.
Y/N tilted her head in confusion, before shrugging her shoulders and allowing the smart second-year to pull her around the unfamiliar streets of Iwatobi.
The two eventually got to Rei's destination-A library.
Y/N stared at the millions of books that decorated the shelves in awe as soon as the two entered the old building. Now if only she could actually understand what the words were...
While Y/N was wondering around the large building, Rei skimmed through a bunch of children books. If he was correct, which he very seldom was, the female only knew how to speak and write. But not read. He was sure it had to do with what she had told himself and the others when they first met, how she had never gone to a real school.
"Alright, I think I got what we need from this aisle-Y/N?" Rei blinked in confusion as he didn't see any sign of the (H/C).
A look of worry crossed his features, as he frantically looked around the area he had left her in. But there was no sign of her. And just as he opened his mouth to shout for her, which was very risky since the librarian was very strict as well as terrifying, he yelped in surprise as a book was thrusted into his vision.
"I found something I can read!" Y/N exclaimed, in a lower tone than usual that caused Rei to somehow figure out that she must have run into the Librarian during her disappearance.
The megane stared at the book, then at the cheerful female with a quizzical look. "Atlantean?" He asked, only to receive an excited nod. Rei sighed and held up the stack of books he had picked out. "Let's start with these first." He suggested.

-6 hours later-Iwatobi High Pool-
Y/N and Rei stared at each other with a deadpanned expression.
"I thought you said you were going to teach me different strokes." Rei bluntly stated.
"No." Y/N shook her head. "Just get better at Butterfly." She told him.
Rei groaned, sinking under the water just a bit, while Y/N continued to stare at him with the poker faced expression.
Eventually, a huff left the female's lips, and she allowed herself to float on her back and she closed her (E/C) irises.
Glancing at the (H/C) after his small fit under the water -he was mostly cursing himself at his misunderstanding of the situation-, Rei realized how much Y/N looked at home in the water. If he didn't know better, he would mistake the new team member as Haru's sister.
The goggle-wearing male stiffened as he felt Y/N's head hit his chest. As he glanced down, she glanced up and sent him a goofy grin.
"You don't have to continue teaching me." She stated, her tone hiding a hint of regret. "I can get Mako to teach me if I'm too much of a bother."
Rei looked at her in shock. "N-no! I'll still help teach you! That's what you asked me to do, right?!" He stuttered out quickly. He didn't mean to make her feel bad!
Y/N looked at him in confusion. "But I can't help you with swimming." She pointed out.
Rei clicked his tongue and turned his head away from Y/N, a faint pink dusting his cheeks. "I'll find some other way to learn, I'm smart, you said so yourself!" Rei exclaimed, freezing as he heard Y/N giggle. "I'll continue teaching you because you need to know how to read in order to get through life. All I want in return is you putting effort into your studies." He told her.
A grin decorated her lips, as Y/N closed her eyes and hummed softly as she nodded in agreement.

(Fun fact: I actually used to be on a swim team, from 4th-7th grade. I was best at Freestyle and Butterfly/Mermaid stroke rather than the other two. I was also thinking of joining my highschool's swim team next year/my Junior year.)