This was inspired by the various faint Hisa x Yumi fanart I saw around the net. This has no bearing on Fireflies and serves merely as a simple one-shot.

A Mistake

Yumi was so focused on her online game that day in the club room that she barely noticed when everyone left already. She had been lucky enough to draw herself into early riichis all day, and wasn't planning on letting go of her climbing winning streak. It was a habit of hers that persisted until she ran into a crushing defeat by any of the anonymous pro mahjong players that occasionally frequented that mahjong lobby, at which point she'd call it quits for a few hours. It was hard to stay away from it for too long, after all.

She leaned back into her chair, which faced away from the door, after calling riichi once again and took the chance to stretch her arms a little as the mahjong client went on autopilot, waiting for her tile to appear. When it did, she gave an inner smirk of triumph and collected the points of her ron. The door opened briskly. It was, perhaps, unlucky then for her to gain only a very small sense of self-awareness as the details of her winning hand appeared onscreen.

"What is it Hisa, dear? Did you leave something here again?" Yumi queried the person absentmindedly, forgetting where she was, as she usually played online mahjong only in her room.

A pregnant silence filled the room, and the purple-haired girl quickly checked herself, her face losing its color as she realized where she was, and who the newcomer was likely to actually be. The feeling of dread that was spreading through her body only worsened as she felt the ominous aura of the person behind her. She swallowed her fear nervously.

"Ah… Momo…?" She turned, greeting the younger girl tentatively.

Yumi instantly realized things were very, very bad when Momo refused to appear. She started to sweat a little, her imagination running wild as all sorts of horrible headline news titles ran through her mind. 'High School Girl Is Found Dead Through Mysterious Circumstances.' 'Promising Mahjong Finalist Dies In A Freak Accident.' 'Recent Murder Has Proven That Mahjong Tiles Can Be Used As A Killing Weapon.' 'The Corpse Of A High School Girl Is Used As Proof That Tsuruga Academy Is Haunted.'

"I wonder what's going through that wonderfully nimble mind of yours, sempai?" Momo asked kindly, appearing with a deceptively sweet smile. "It's making all of these deliciously interesting faces. I hope it's nothing… foreboding," she finished threateningly, eyes demanding a reasonable explanation or else there was hell to pay.

"No, no. Of course not!" Yumi laughed nervously, struggling to remember what she accidentally blurted out earlier, so used was she to saying it. What was it, what was it? She must have at least said Hisa's name, but what else? How much can she wave away as mere coincidence? "I was just… daydreaming, that's all! It suddenly turned out very strange towards the end, I might add. Really, Hisa Takei appeared and I just had no idea what to do with her. You know how those club presidents are…" She tried to laugh again, but found her voicebox had constricted in paralyzed fear of Momo's blazing green eyes.

The black-haired girl ran her fingers up Yumi's arm seductively. "Hm, now that you mention it, I don't. I don't know anything at all about club presidents. Maybe I should pay Kanbara-san a visit~" Her normally innocuous '-su' suddenly took on a dangerously suggestive meaning, and the older girl impulsively reacted, grabbing Momo's arm as she stood up.

"You can't be serious! Kanbara?!"

Momo carefully disengaged her arm from Yumi's panicked fingers. She tilted her head to the side thoughtfully, the smile never leaving her face.

"Well, she does happen to be refreshingly honest about everything. I wonder if maybe I've had my sights set on the wrong person this whole time…?"

No, no, no! This could not be happening! This was outside her realm of expectations. Momo… Momo liked her! She wouldn't just spontaneously transfer her feelings like that!

Not like you, right?

The incriminating voice in her head echoed inside so loudly that she almost thought that the other girl could hear it. That was different! Hisa just happened to be a very good friend that helped her sort out her feelings for Momo. Sure, she came over often, but isn't that what good friends do? Momo was different. She couldn't afford to lose her.

"Momo, please…" She begged uncharacteristically. "I'm sorry. I didn't mean it. You're the only one I want." The deep red blush that formed at the rawness of her words only helped further her cause. Or so she hoped.

But Momo would have none of it. Her mind was made up. "I don't understand what you're talking about, sempai. Excuse me, but I have to meet with Kanbara-san now."

And with that, the de-facto leader of the mahjong club was left bereft of her most ardent supporter, in more ways than one. The laptop screen flashed behind her, signaling her defeat in the mahjong game that she had abandoned.

"…and I just don't know what to do!" Yumi fell backwards onto her bed, cell phone attached to her ear. She took little comfort in the springy softness of it, instead preferring to focus on the issue at hand.

"Well, have you tried approaching her about it?" The voice on the other end asked kindly, a note of amusement slipping into her voice.

Yumi exhaled impatiently. "Yes, I have – and don't you dare laugh – but every time I try to approach her, she's always with Kanbara and pretends she's too busy to leave her."

"I'm trying hard not to, dear, but you're making it difficult for me to take you seriously. What happened to that brutal bluntness that endeared you to that cute little girl, anyway?"

"It's gone. All gone," she responded glumly. "It's so frustrating! I can't even talk to Kanbara herself about this because she might actually like Momo that way, in which case it would be ridiculous for her to help me."

"You could just grab her and kiss her when you see the girl," the voice advised cheekily.

"Hisa! You're not helping at all, here! Agggh." Yumi groaned, grabbing her head in both hands in frustration.

The girl on the other end continued, "I could even come over and help you practice, just like we used to. I miss that little trick you did with your tongue-"

She blushed heavily at that and hurriedly cut in. "This and that are different! We agreed that was purely a platonic exercise. This takes precedence over that. Momo could seriously be doing unspeakable things with Kanbara right now. Kanbara!"

"Oh," the other voice responded in recognition. "The president with a weak mind. Yes, that is serious. What if that stupidity is infectious?"

"Putting aside the fact that you just insulted my best friend," Yumi said dryly, "I'm glad you're at least listening to me now. Do you think there's anything I can do to fix this? I mean, half of this is your fault, after all…"

"Ah, Yumi-kun is so assertive now. I think I miss having the shy Yumi-kun around…" Hisa continued seriously, "Well, all she really wants is attention and the reassurance that you're not doing anything with me, now or otherwise. Things should fix themselves if you do something bold in front of a lot of people. That way you can't take it back."

Yumi raised a skeptic eyebrow. "How bold are we talking? I'm not wearing anything embarrassing."

"Dear, sometimes pride must be sacrificed in the name of love," the voice explained patiently. "You do love her, right?"

She sighed. "I do. All right. I'll see what I can do."

"Oh, and one more thing. I doubt Kanbara-san even understands what's going on, so don't be too harsh on her when this all blows over."

"It's a little hard to believe that from someone who just insulted her not ten seconds ago," Yumi said wryly, "but all right. Thanks, Hisa."

"Anytime."

Click.

The next day, a new legend was born. It told of a high school senior who vandalized the windows of the all-girls school she attended to proclaim her love for a fellow schoolmate. It was said that even as she was scolded by various school officials, she refused to list her love as an accomplice, despite the fact that the latter girl's name was spray-painted all over the windows with the words 'love','want', and 'you' next to it.

Those who saw her now often said that she seemed to be holding something invisible in her hand at all times, and never let go of it. One would also often catch her talking to herself on the roof, or doing something odd that would cause her to blush uncharacteristically when caught.

Existence was a strange thing, after all.