For Nanami, studying was how she relaxed. The roof of the school was a good place for it - nobody came up there but her. Life was complicated; people especially, were complicated and exasperating. By comparison, math formulas and dense textbooks were simple and easy to understand. Quadratic equations didn’t have hidden meanings, layers of subtext, or raging teenage hormones to get in the way of understanding. People like her childhood friend Makoto who couldn’t get it through his skull, which was thicker than battleship armor, that she might just be kind of interested in him as more than just a childhood friend, were even more exasperating than most.

It wasn’t that they were cold or distant or anything. Far from it; they walked home together each day, living just across the street from each other. They ate lunch together. They could talk for hours. But they were just friends. Makoto treated her like one of the guys, not as a woman! He wouldn’t even be so kind as to let a joke about how they may as well be a couple go without a retort!

Of course… she didn’t do that either. She didn’t mean to be rude, really. She just got flustered, or annoyed when he didn’t recognize her advances as what they were. It wasn’t her fault if she was embarrassed to come out and say it! A good confession needs to have some subtlety, you can’t just be blunt about it! She looked nice enough - she might have been flat but she thought she had a pretty face and nice hair and eyes. He should have been coming on to her! And… she was smart enough to realize that she was just making excuses for her complete inability to be straight with Makoto. She hung her head and sighed. She herself was nearly as much an obstacle as Makoto’s being as dense as a neutron star.

“Had another fail with Makoto?” A cheery voice said from beside her said.

“Ah!” Nanami cried out, dropping her textbook and flailing to catch her laptop, just in time to avoid it hitting the ground. “Damn it Hoshi, how did you get up here so quietly? The door’s rusted, it’s not quiet!”

“I’m taking lessons from my cat.” Hoshi said cheerfully, plopping herself down beside her studious friend. “Wow, your first instinct wasn’t to deny it, it must have been bad…”

Nanami blinked. “I, uh, what, uh-”

“I can wait.” Hoshi said patiently.

Nanami sighed. “...It was bad.”

“I figured. I’m smart like that.” Hoshi grinned with satisfaction, before switching to ‘concerned friend’ mode. “You ok?”

“I asked him to meet me behind the school…” Nanami started.

“I heard the rumors… I was shocked you’d go with something right out of a visual novel.”

“I started the rumors, and that was intentional. I figure, if I make sure he knows dang well what it is, even Makoto can’t be that dense, right?”

“Makes enough sense,” Hoshi conceded, “And then?”

“And we met up… there was a cherry blossom tree and everything… and…” Nanami hesitated.

“And you couldn’t do it.” Hoshi finished for her.

“And I couldn’t do it.” Nanami said. “It’s just… I got so flustered. I thought, ‘oh god if I do it like this he’ll never let me hear the end of it,’ and ‘he’ll laugh it off and say I’m acting like a child’ and I turned bright red and just asked if he needed help studying…”

“And then you threatened him.” Hoshi prompted.

“And then I threatened him that I’d make sure his parents found out if he dropped any places in the rankings so he should take advantage of it. Then he laughed that damn laugh.”

Hoshi put a hand on Nanami’s shoulder. “It’s fine, isn’t it? This isn’t any different than usual, right?”

“This time it’s not even him failing to take the hint, though.” Nanami said, “I set everything up, I made sure it was clear what I was doing… and then I didn’t. He’s not even the problem at this point, it’s the fact I can’t just be straight with him. It’s not his fault if he doesn’t get it if I do everything in my power to make him think otherwise. At this rate the best I’ll ever do is friends because apparently I’m physically incapable of sharing my damn feelings!”

Nanami took a few deep breaths as she realized she’d started to raise her voice. “...Wow, sounds like it went worse than I thought.” Hoshi said after a while. “You need a hug.”

“I don’t-” Nanami started, but Hoshi was already hugging her so she didn’t bother to complete the thought. “...Thanks. Sorry for shouting.”

“No no it’s fine, I get that you’re frustrated.” Hoshi said, nodding. “I guess you need some help, huh?” A concerning grin was crossing Hoshi’s features, and Nanami knew that look.

“Look, I don’t need any of your occult nonsense to get Makoto. I’m a woman of science, not astrology and fortunes.”

“Are you going to scientifically bag Makoto before he gets with another girl?”

“...I’m going to regret this…”

----------

“I already regret this. I feel ridiculous. I’m going home.” Nanami said. After school, she’d told Makoto that she and Hoshi were going to study at the latter’s house so Nanami wouldn’t go with him like they usually did. Of course, snarky idiot that he was, he made a joke about it, Nanami snapped at him, and she felt like she had a rain cloud over her since that point.

“Oh come on, Makoto already left so you can’t go with him, what’s the harm? Do you have anything to lose?” Hoshi sing-songed as they walked.

“My dignity?” Nanami said.

“You lost that when you planned to ask him out behind the school under a cherry blossom tree.”

Nanami’s mouth worked but she could come up with no response. Instead, she checked her phone. The GPS said they should be near their destination…

Soon, it was in sight. An old torii-style gate marking the small, simple shrine next to a similarly small public park. Surprisingly, it wasn’t covered in graffiti and actually seemed in nice condition, which made Nanami feel a little less ridiculous. “Supposedly,” Hoshi was saying, “This is a shrine to a mysterious god, or maybe spirit, of luck. They say if you make an offering here there’s good odds it’ll come true!”

“Who’s they?”

“You know,” Hoshi waved vaguely around, as if indicating… well, everything. “They!”

Nanami shook her head. “Whatever. And what’s with the cat statue?”

“It’s a cat goddess. Or spirit. Or maybe they were just marking the place to put the offering.”

Nanami sighed and, feeling ridiculous, placed her offering of rice and salt (she’d have gone for sake too, but she wasn’t able to buy any) in front of the statue. “I don’t know if you’re real but I’m desperate. Please give me the ability to be more honest to Makoto, and appealing enough for him to accept my feelings… I’d really do anything at this point…”

After completing the appropriate rituals, Nanami sighed again. So desperate that she’d turn to this. She was pathetic. “Well, Hoshi, since we’re out here anyway, wanna go get something to eat?”

“Oh, do I!”

----------

Makoto was looking forward to a nice Sunday; some tests were coming up and, despite the concerns of his friend Nanami, he was reasonably confident that all he had to do was study a bit and he’d be fine. He was hardly top of the class like she was, but he wasn’t the bottom either. So he figured he could get away with a bit of personal time between studying - after all, just burying his head in books wouldn’t help him much.

He idly wondered if Nanami would show up that day. She often did - either to study, to make him study, or on rare occasions (usually post exam) to hang out. That exchange from Saturday had been a bit… odd. For half a second, he’d thought Nanami was going to confess to him, anime-style. But then she’d gone on the usual spiel about studying.

Heck, what would he have done if she had asked him out on a date? Besides turn into a tomato and sputter for a bit trying to process it. Of course, she didn’t seem to be into him in any case, so the question was academic.

As he was finishing his breakfast, he heard the doorbell ring, followed by furious knocking. Right on queue, huh?

He went to the door and opened it up. As expected, Nanami was there, in casual clothes including a hoodie with the hood up and low over her head. “Morning. Isn’t it a bit early to study-” Makoto said, but before he could finish Nanami shoved past him into the room.

“You have to let me stay with you!” she said forcefully.

“I mean, we’ve had sleepovers before, but aren’t we getting a bit old for that…?” Makoto said.

“I’m… I’m serious!” Nanami said. “I need somewhere to stay, something really strange happened-”

“Oh come on, what could possibly be so dramatic…” he trailed off. Nanami had pulled the hood off. Makoto had known the girl his whole life. And he was pretty sure she didn’t have cat ears.

“...I woke up like this.” Nanami said after a bit. The ears twitched a bit.

“I… are they…?”

“Yes! That’s why I came running here!”

“...But why did you think I could…?”

“I don’t know, ok! It just felt right!” Nanami was blushing fiercely all of a sudden - she must have been really mad, Makoto thought.

“Maybe… maybe you should explain this…?”

For the next while, Nanami talked - it wasn’t a long story because, in all honesty, she was nearly as confused as Makoto was. She’d gone to bed completely normal. She’d woken up with cat ears. She’d freaked out and come running for reasons she frankly didn’t understand, it just kinda felt right, and wanted to stay with him while they figured it out.

“Well… I…” Makoto sighed. “I can’t just say no… I’ll sleep on the couch, you can take my bed.”

----------

They spent most of the day trying, and failing, to figure out what happened to Nanami, via research. There was a big problem with that, though - namely, that there was no way that anything like this was recorded in any kind of scientific journal, which meant they were sorting through urban legends and myths, some forum shitposts, and trying to avoid too much hentai.

“This is infuriating… even if we do find something like this, it’ll be completely impossible to verify…” Nanami grumbled.

“...We should continue tomorrow.” Makoto said. “It’s getting a bit late, and I don’t know if we’re finding anything… maybe sleeping on it will help us figure something out.”

“Are you sure you want me on the bed? I can sleep on the couch…”

“Really, it’s fine!” Makoto insisted. “I’ll be in the next room if you need me.”

With that, he left the bedroom and left Nanami alone. The cat-eared girl put her laptop to the side and sank onto the bed, rubbing her new ears and thinking.

She thought about a lot of things. Of course, there was a lot of ‘why did this happen to me’ and trying to think of potential causes. This wasn’t some anime, it wasn’t like she’d been asked to drink some shady concoction or been kidnapped by a mad scientist or anything. She dismissed the idea it had anything to do with the cat-deity she’d said a prayer to as well, since obviously magic stuff wasn’t real. Of course, catgirls weren’t either, and yet here she was.

Then her thoughts drifted to what she’d done. Why had Makoto been her first instinct? Sure, he was smart, but he wasn’t magically going to know more about her situation than she was. She had the same kind of privacy he did, so shutting herself away could have been an option - but then, she didn’t think she could take it alone. As chilly as she could be, she wasn’t made of stone; nobody could go forever without human contact. Makoto had her friend since childhood. If anyone was going to not freak out and throw her to the street it was him.

And despite him being such a nice guy - when you got past the snark and all, which he’d thankfully been restraining since he saw how distressed she was - Nanami still couldn’t be honest with him. Couldn’t tell him her feelings. If she figured out what was going on with her and found a way to reverse it, she’d tell him, she decided.

She was thinking about that as she realized she was in his bed. She could smell his cologne, she was trying to sleep in a place he’d made his own. She blushed a bit. She blushed a bit more as she began to contemplate what he might have thought of while he was laying here - had he ever… thought of her-

Nanami shot bolt upright and tried desperately to purge the thoughts from her head, blushing scarlet. What the hell was she thinking about in his bed!? Come on, now of all times!? She was so frustrated with herself that at first, she didn’t notice how she was changing. It was hard to notice her bottom swelling beyond a slightly different angle to stare at the wall from. A little extra weight on the chest went unnoticed. What got her to shout was the odd feeling in her bottom as something stretched and grew.

“Aaah!” she shouted, and for a few seconds she tried to figure out what it was, but she felt pressure building on her ass and couldn’t let it go unresolved - she pulled down her pants and sighed in relief as the pressure was released.

“Nanami! Are you-” Makoto shouted as he barged into the room. Nanami stared at him - she was blushing fiercely, had her pants and undergarments down, was bent over… it probably looked like…

“Close the door!” she demanded, picking up the nearest thing and throwing it at him. “I-I’m not- I’m not doing that!”

Makoto slammed the door closed before the mug could hit him (plastic and not breaking, thankfully). “I-I-I’m sorry…” he stammered through the door, “But, uh, tail?”

Tail? What was he… Nanami blinked as she reached to her behind and felt something fuzzy. And… felt her hand on that fuzziness. She brought the thing around to see a tail, the same light brown as her hair. She let go of it. It didn’t fall, and she could still feel it as it swished around. “What the hell?”

“I, can… can I come in?” Makoto asked.

“...Yes.” Nanami said after a bit.

Makoto opened the door, slowly, and pointedly looked away from Nanami. “So… you seemed to transform a bit… more…”

“...Yeah.” Nanami agreed. “The tail… and…”

“And?” Makoto said, confused.

“I… I think my butt got bigger. And my… chest.” Nanami said, blushing.

“Oh… right… do you… know what caused that?”

Nanami blushed fiercely. It hadn’t been happening as she was drifting off to sleep. No, it had happened as she thought about Makoto… in a certain way… and had certain feelings…

“N-N-No I don’t.” Nanami said. “I’m just as surprised as you…” It couldn’t be something like that that triggered it. That would be ridiculous!

Soon, though, it was clear that the changes had stopped for the moment, and they went back to sleep as best they could…

----------

It was a couple of days after Nanami had come to stay with Makoto, and he’d had to return to school while Nanami stayed in his home. There was an explanation about some family tragedy and such, since otherwise her absence would be rather noted. While there were some raised eyebrows at the suddenness and informality of it, Nanami’s previously perfect attendance record soothed concerns.

Nanami felt like she should have been more worried about that. She usually hated missing school - and she hated lying to teachers more. But she found it oddly far from her mind. She tried to pass what time wasn’t spent attempting research trying to study and do homework, but concepts she’d grasped easily days before were slipping from her. Had missing a couple days of class really put her so far behind?

She was frustrated by that… and to a degree by Makoto. Since her transformation she’d been thinking about him a lot. Even more than she usually did, which wasn’t a small amount. She’d found it harder to be her usual self to him and had strange urges towards being significantly more affectionate.

This was the case as she was trying (not very successfully) to relax. Makoto had gotten home recently, and they’d had another round of attempted research which continued to turn up nothing. Nanami couldn’t help herself, and glanced towards Makoto - in time to see him hurriedly look away from her. “What is it?” she asked.

“...I don’t know… just wondering about things.” Makoto said sheepishly.

“Like?”

“What’s the tail feel like?”

“Oh.” Nanami said, wincing. “It’s… taking some getting used to. I’ve had to start wearing skirts, and I might just have to suck it up and take some scissors to my clothes… it’s really uncomfortable to deal with.”

“It’s kinda weird to think of having fur… how does that feel, anyway?”

“Honestly? Surprisingly soft. I don’t know what I expected. Human hair, I guess? That’d have felt weird.”

The two were quiet for a bit. Then, Makoto broke the silence. “Can I see how it feels?”

“Huh?”

“Can I touch it a bit? I’m curious.”

Nanami blinked. She was… kinda surprised, but at the same time not? Normally, she’d have slapped him for the suggestion. But for some reason, she didn’t mind the idea so much. “...Sure? It’s not like it’s something I’m usually supposed to have… so it shouldn’t be embarrassing…”

Makoto moved from his desk to sit beside her on the couch, and without preamble got to gently touching the tail… evidently, he didn’t see anything embarrassing about it either. Not that he should, Nanami thought to herself. “You weren’t kidding, it really is soft… you really feel this?”

“Sort of the same way you feel your nose or something, yeah. You know it’s there but it’s not really something you consciously move around so much…” Nanami said, trying not to blush as she felt him stroking her tail.

“Yeah… it’s hard to think it’s connected to you, it does feel like a real cat’s tail…” Makoto said. He stroked a bit harder, and Nanami began to realize it felt… good. Really good. Kinda like she’d felt the other night- oh, crap.

“Hey, maybe you should be a bit careful-” she started to say. Then, the doorbell rung and Makoto, in his surprise, accidentally pulled on her tail. “Aaah!”

“S-Sorry, I’ll get it, you just try to keep out of the way-” Makoto said, standing and dashing to the door without noticing the state he’d left Nanami in.

The unwilling cat girl was blushing fiercely, staring into space. Something about that handling of her tail had felt astonishingly good, and… definitely in a certain sort of way. She was still stunned by the sudden burst of pleasure, to the point that as her breasts began to swell and strain her shirt, she didn’t really notice. And frankly, if she had noticed, she wouldn’t have cared - it was like her common sense and intelligence was draining from her head and into her bust and that made it more than a little difficult to figure out why continuing transformation was a bad thing.

“It was just a food delivery-” Makoto came back to see Nanami staring off into space with a dumb grin on her face, newly enlarged breasts straining against her shirt. “N-Nanami!? What happened? I was gone for minutes!”

Nanami’s eyes refocused. “What… I don’t think I get it, nya. Could you keep rubbing my tail? That felt nice.”

“Nanami? Are you ok?” Makoto said, his tone worried.

“Nya, of course I am! Hey, do you smell something nice?” She took a few sniffs of the air, trying to determine the source. She had the sense she should be worried about something, but it was rather hard to make herself care.

“Nanami…” Makoto started, but the cat girl stood and walked over to him, sniffing. She got… very close, close enough that he very pointedly looked upwards so that he wouldn’t get an eyeful of cleavage - Nanami’s shirt was barely holding together.

“Hey, what’s in the bag? It smells good.” Nanami reached down and snatched the bag away, sniffing closer.

“It’s just some sushi I ordered-”

“Fish!” Nanami exclaimed as she looked in the bag and took out the food. Without preamble, she forced open the container and started eating…

----------

Another couple days had passed, and Makoto was more than a little worried about Nanami. She’d been changing a lot - and not just physically. The physical changes, as… visible, as they were, were secondary in concern to the mental. She’d become basically useless in research, more concerned with affection and food. It was hard to see any semblance of her old national-level intelligence, and besides book smarts she seemed to have dropped the better part of her common sense.

That morning, Makoto felt oddly warm as he woke up. And kinda heavy. He groaned softly as he came to wakefulness, and began to realize it wasn’t that he was heavy - it was that something was on top of him.

“Good moooorning~ Nya~” a cheery voice said.

“Good… morning?” Makoto said, blinking the sleep away. That had been Nanami… but where was she?

He had a sinking feeling about the weight.

Makoto threw off the cover and Nanami was there alright… buck naked and on top of him. “N-N-N-”

“Shhhh~” Nanami said, putting a finger to his lips and grinning like… well, a cat. “I just wanna tell you… I love you, you know, nya? I don’t know why I couldn’t say it before…”

“Nanami, I don’t think…”

“Nanami may not be very smart, nya… but Nanami knows this much! She loves you lots! Nanami just wants to stay with you. That’s all it’ll take to make her happy, nya!”

As Nanami talked, Makoto watched her change further. There wasn’t much left to change - he figured most of it was going on in her head, making her even dumber than she’d become. But the big visible change was in her eyes - they looked far more feline than human now.

“I… I love you too, Nanami…” Makoto said softly. He had for ages, but wasn’t sure how to actually say it… “But… I loved the old you, too…”

The cat girl tilted her head, blinking in confusion. “The old Nanami? What’s that?”

Makoto sighed, and just started petting Nanami on the head gently. She settled against him, purring like a cat.

After that, it was clear that Nanami as he knew her was irrevocably changed; in the days to follow, as far as he could find, there was no way to return her to her previous self. But… well, she seemed happy. Far less stressed, more cheerful than he’d ever seen her. She’d lost a lot of intelligence, too much to return to human society even if it weren’t for the physical transformation. And Makoto wasn’t about to kick her out, so instead he did his best to provide her with all the affection and food she wanted. Hers was a simple life, but she evidently loved it.

Makoto did wish he could turn her back - he didn’t need the big tits and bottom, or the way she was so physically affectionate. They were nice, but he’d been fine with how she was before. Still, the new Nanami wasn’t so far removed from the old in some ways; when they got deep in a conversation, he almost forgot she’d changed at all. Their relationship would survive intact. And at this stage, if he could make her happy, he’d be satisfied with that.