"Put every variable in, she said," Touma muttered scribbling in his notebook. "Then you might get it, she said… But maybe you are too dense… Well, sorry but I'm not a genius from an elite school…"

The variables kept clashing with each other, no matter how he put them around. Maybe it wasn't a simple addition, after all. But Mikoto hadn't given him a formula and he couldn't really call her and ask. Just imagining her grumble "I can't believe you can't solve this" made him want to shove his phone as further away as possible.

He smirked. "Oh, you will regret this, Biribiri… I got just the right wish for you… Will wipe that smug grin right off your face…"

"… an…"

Something echoed in the distance, like from a faraway land... too weak to get through the storm of thoughts.

Mikoto… she hadn't been smug… had she? Looking back, all he could remember was the daring look she had in her eyes. As if saying, "Do it, idiot. Prove me wrong".

He sighed and scratched his temple with his pen.

"… ou-chan…"

Figure out what you are to me… How do you even do it? This equation was just impossible to solve.

Seriously, leave it to Misaka Mikoto to confuse the hell out of you…

"Agh, so annoying!" Touma growled ruffling his hair.

Someone near him yelped, and he jumped up in his seat. He looked around the empty classroom with bewildered eyes. Was he so focused on the equation he missed the bell? His gaze shifted and he froze. Beside him stood Komoe-sensei, her small frame crouching in heap, like that of a scared animal.

Had he just yelled at his teacher?

The silence filling the room made his gulp all the more audible.

He leapt almost knocking over his desk and bowed his head low. "I'm sorry! That wasn't directed at you, sensei!"

Komoe relaxed; however, her face instantly darkened.

"It's good that it wasn't. But you should pay more attention to your surroundings, Kamijou-chan. You'd have been in big troubles if someone less forgiving was in my place," she said with as much strictness as she was capable of.

And if everyone was still here, he would've been lynched for sure. His classmates were very protective of their tiny teacher. Hell, Aogami and Fukiyose would've tied the rope around his neck themselves, with Tsuchimikado snickering somewhere in the back and Himegami offering a prayer for his soul.

He shuddered from the image. For once, his rotten luck didn't screw him over.

"You may rise," Komoe said in a softer tone. "I was just leaving when I heard a voice. Someone sounded rather frustrated. Are you preparing for the exams?" she asked glancing at his desk.

Touma hastily closed the notebook and started shoving everything in his bag. "Yes… for the exams…" he muttered. "I gotta go…"

He could continue at the dorm. Index would probably be at the church, and Othinus wouldn't bug him over simple stuff, so…

"If you are having troubles, sensei is here to help," Komoe suddenly said.

The bag almost slipped out of his hands.

"Err… I doubt you can. This equation is just impossible to solve."

She frowned. "We don't give you something you can't solve. Unless you are tackling Hilbert and Landau… But even the brightest minds of Academy city can't crack those."

"No, no. It's… a personal thing. A challenge from… someone. There are too many variables to count and I don't quite understand the rules."

"Seriously, Kamijou-chan… You don't have time to waste on such silly things. Chances are this person just pranked you."

"She wouldn't…!" Touma protested and immediately fell silent. Did he really just raise his voice at a teacher again? What was going on with him?

Komoe looked at him, lips curled. "She wouldn't?"

"No…" he said quietly. "If she proposed a challenge, she would play it fair and square. No cheats, no tricks."

With every word, his voice grew firmer, reinforced by conviction.

Komoe giggled, and his cheeks felt strangely hot. "Would this happen to be that overly energetic girl from Tokiwadai?" she asked.

"Well… yes…"

"I see, I see. Well, she did seem very straightforward. If this girl is indeed so fair then there is a solution to her problem."

But it just doesn't make sense, Touma wanted to cry out, when a new voice cut in.

"There you are, Kami-yan!"

He glared annoyed at the door, where a familiar figure with blue hair stood grinning.

Aogami raised an eyebrow at Komoe. "Oh, you are here too, sensei?"

"We were having an unplanned consultation. Kamijou-chan needed some help with… advanced material," she said and looked at Touma. Her lips curled in that same knowing smile. "Although I think he isn't quite ready for it."

Great, Komoe-sensei is underestimating me too, Touma grumbled to himself, his ears burning slightly.

Seeing this, Aogami perked up. "Eh? What's this air of secrecy I am feeling? Why do you speak so mysteriously, sensei? Wait a moment… could this be sign of a forbidden relationship between teacher and student?!"

Touma's jaw hanged open. "Idiot! Where the hell did you get that from?!"

"We've been waiting for you at the gates for the last fifteen minutes and I come here to find you all alone with sensei, whispering about something, exchanging smiles, getting all embarrassed. In this secretive, intimate atmosphere!"

"Intimate?!" Touma croaked.

"Aogami-chan always had a wild imagination," Komoe said and shook her head with a sigh.

Seriously, it sounded more like ravings of a madman. Maybe a good hit would adjust the cogs in that stupid head of his.

Touma took aim preparing to launch his school bag.

"Damn it, Kami-yan! I wouldn't let you woo Komoe-sensei too… geh!" Aogami bit his tongue as a firm hand karate-chopped his useless knob.

From behind him, Fukiyose's scowling face emerged. She pushed him inside the room, then walked in herself.

"Good thing we knew better than trust you with finding Kamijou and not make a fuss over something stupid," Fukiyose said coldly, not even sparing Aogami a glance.

Touma frowned. We? But then he noticed Himegami standing by the door, observing with an indifferent face. Next, a blond mess of hair popped into the doorframe. Tsuchimikado scanned the surroundings and whistled quietly.

Aogami mumbled something.

"I believe he said "Demon woman"," Tsuchimikado supplied.

Fukiyose huffed and deliberately turned away.

"Now that the ritual is done, how about we go already?" Himegami said.

"Go where?" Touma asked confused. "Why are all of you here?"

His classmates exchanged looks. Ire and amusement quickly changed to puzzlement.

"What do you mean why? We were going to grab some burgers after school," Aogami managed wincing.

"You said you'd catch up," Himegami added in a plain voice, yet her eyes narrowed slightly.

Did he?

Touma thought back but all he could remember were the two dreadful columns. How absorbed had he been to forget that?

Tsuchimikado sighed. "I told you he was too focused on his scribbles. Honestly, Kami-yan, this is starting to turn into an obsession."

"It's not!" Touma growled.

Sure, he had been getting distracted lately. Burnt quite a few meals, chewed on far too many napkins that came with the sandwiches. But so what? Mikoto's challenge hadn't been on his mind 24/7. He also had been cramming for the exams and it didn't really mean anything that occasionally he would space out thinking of her… the memories they shared. That had mostly happened during breaks… very rarely in class… and only closer to the end…

But then the equation would call to him in the middle of a grocery run. His body would navigate the shelves on its own as the mind picked apart another memory. Analyzing every gesture, every gaze, every word in a vain hope to find some kind of clue. Only to discover at the register some pricey goods that had sneaked their way into his cart.

Alright, perhaps, he was focusing on this bet a little too much. But only because he wanted to win. And that still wasn't an obsession!

As Touma was fuming to himself, Komoe chuckled lightly.

"Kamijou-chan is trying very hard to solve quite a difficult problem," she explained. "So hard that he might be overdoing it. I think he needs to unwind a little. Could you help him?"

Fukiyose cocked her eyebrow and sized Touma up, then looked at the others. The boys smirked while Himegami nodded ever so slightly.

"I guess we should work up an appetite for those burgers. We are going to the park to play basketball!" Fukiyose announced, lips curling. "And whoever loses pays for everyone."

At that, Touma's eyes almost popped out of their sockets. "Come again?!"

"Park, basketball, losers pay," she repeated with a grin. "Two on two. Aisa will referee."

He thought about making a run for it. There was no way he would participate in something like that, not with his rotten luck. He'd be the loser the moment he stepped on the court. More so, he was willing to bet he'd be the only one paying.

Just as he moved to escape, Tsuchimikado and Aogami flanked him at both sides and held him still.

"Come on, Kami-yan, it'll be like good old times," said one with an eerie smile.

The other one smirked. "Yeah, you'll just throw the ball around, give that body of yours a good jolt, then grab some burgers… and pay everyone's tab…"

He knew it…

"I've not agreed to this!" Touma protested as they were escorting him out. "It's basically an extortion… Sensei, sensei! Help!"

But Komoe simply waved him a farewell.

Traitors, every damn one of them…

The spring breeze cooled Touma off a little. He took a deep breath and admitted his body could use the exercise. Hunching over the textbooks day after day had taken its toll. He even entertained an idea of winning.

Which dissipated once he got teamed with Aogami

In any other situation, that wouldn't be a bad thing. Aogami was pretty fit and had good reflexes. The problem lay with their opponents – Fukiyose in particular. She might have been Aogami's natural enemy, but she also happened to be his biggest weakness.

"Damn you, Aogami, watch the ball!" Touma cried out just after Aogami let Fukiyose pass him and score.

"But I do, Kami-yan! I watch both of them boun… Begh!"

The ball hit the blue-haired idiot right in the head.

"Referee!" Touma called as Fukiyose strode by unconcerned. "That gotta be a penalty!"

Himegami looked away from the fluffy clouds and said, "My apologies. I stopped paying attention after Seiri-chan scored."

Touma let out a long sigh.

That was pretty much how the game had been going so far. And yet his team was still ahead by one point. Fukiyose's aggressive play style had led to some actual penalty shots which Himegami couldn't overlook. Unfortunately, the other team wouldn't let that advantage grow too big.

Touma picked up the ball and shoved it in Aogami's face. "Focus on this ball, dumbass! Remember! Orange, rubber, bounces on the ground and not under the shirt. Got it?"

"Geez, Kami-yan, you worry too much. Ease up, or else you will go gray before graduation."

It took great effort not to smack that clown. They were so close to victory, there was no way he could relax.

"One minute remaining," said Himegami approaching them.

Touma handed the ball over and she walked to the center of the court. There Tsuchimikado waited with a grin that made Touma shiver. What scheme had this villain cooked up? Ignoring him could be detrimental. But so would be not watching the ball.

Himegami moved to toss the ball up. Touma was about to jump when…

"Hey, Kami-yan," the crafty bastard said in a nonchalant voice, "bought a return gift for you girlfriend yet?"

Touma was about to retort on reflex – and then froze. Thoughts scattered about like ants in his head. Return gift. If you got chocolate on Valentine's, you are supposed to get that person something on White day. That is the tradition.

And he had forgotten completely about it.

The ball shot up in the air; Tsuchimikado jumped smirking in triumph and slapped it. The sound brought Touma out of his stupor, but he could only curse. The ball was flying towards Fukiyose. She moved to catch it – eyes on target, face a mask of determination.

Aogami cut in snatching the ball right from under her hands. Touma ran to the opponents' hoop to support his teammate. The damn idiot was useful after all, as long as Fukiyose with her assets wasn't in his face. They could still do it…

But then Tsuchimikado blocked Aogami off. Aogami tried to go around – and got cut off by Fukiyose. Dead lock. He twisted and turned in desperate attempt to break through, while keeping the ball away from their opponents. In the end, he grunted and jumped as high as he could.

"Kami-yan, catch!" Aogami said throwing the ball.

It hit the ground and hopped along the court. Fumbling, Touma almost tripped, yet somehow still managed to pick the ball, then took aim and threw it. The trajectory was on point and there was just enough force. It should have been a perfect shot. But just as his luck would have it, the ball hit the hoop and bounced right out of the basket.

Of course, the one to catch it was Tsuchimikado.

"Ah, shit… Aogami, fall back!" Touma shouted already seeing where this was going.

And sure thing, just before he could block him off, the blond bastard passed the ball to Fukiyose.

The defacto class rep was going for the hoop, with only the class rep in name standing in her way. Touma tried to intercept her but Tsuchimikado kept cutting him off.

"Aogami! Don't you dare miss that ball!"

"Haha, no worries! I'm in the zone. She is not getting past me!"

That smug look… he better not be all talk. But at least he wasn't just standing there gawking.

And then Tsuchimikado shouted, "Ah, damn, I don't think we can win this now… If only Fukiyose had some kind of trampoline to step on!"

Immediately, Touma's face froze – just as Aogami's lit up with delight.

"On it!" he said…

And then the damn bastard fell down on all fours.

A normal person would have stopped at such a sight utterly dumbfounded. Fukiyose simply kicked off the make-shift support as if it was the most natural thing to do. Like an eagle diving for its prey, she flew towards the hoop and slammed the ball in.

It hit the ground – and so did the boy's heart.

"Game over! 22 to 23, Seiri-chan's team wins!" Himegami announced and clapped unenthusiastically.

"Yes!" Tsuchimikado jumped up in joy and ran off to high-five his teammate, while Touma wobbled towards his.

Deflating with every step.

"Kami-yan… I ain't apologizing for that," Aogami warned when he approached. Despite sprawling on the ground, that blue-haired bastard was smiling ear to ear. There was a clear print of Fukiyose's shoe on his back. Like a stamp or a… lipstick kiss?

Touma wrestled with the urge to kick the traitor but in the end he was too dejected for it.

But before he could curse his rotten luck, Aogami said nonchalantly, "By the way, would you mind covering my share? I'm kinda broke right now. There was this figure I really needed to have, haha… oww!"

Touma walked over his useless friend, smudging the print, and left the court.

In the end, he paid for everyone all on his own.

They got a table and dag in the moment their meals arrived. Judging from his friends' faces, it must have been the juiciest burgers in the world. And yet Touma felt no appetite. All he could think about was his diminished bank account. His brain kicked into high gear working out a plan to cover for the expenses. He could always cut down on the snacks and desserts. Index might rebel without her fix of sweets but that wouldn't be the first time. If worse comes to worst, he could always send her off to the Amakusas.

Speaking of which, they had been making such good lunches for breaks during the renovation works. If he pitched in over weekends, he could bring some home. Knowing Itsuwa, there would most certainly be leftovers. Although… they might be on a tight budget themselves. It would be rude to impose on their generosity.

Well, there is always the proven method, Touma thought grimly. Just hunker down and wait till the next allowance. Gotta check for sales when I get back home… At least, I still have money and the ATMs are working. It won't be another New Year's.

He shuddered remembering the ordeal. His stomach chimed in with a growl. He looked at his burger, still untouched, then at his friends radiating delight. The growling got louder earning him looks. At last, he took a bite. Immediately, all the bad thoughts got washed away.

The others exchanged smiles.

"Easy there, Kami-yan, or you will choke," Aogami teased.

"Told you, tastes just heavenly after all the exercise," Fukiyose said.

Himegami backed her up with a few nods, even though she herself had spent the whole game on the bench.

"Especially when you aren't the one paying," Tsuchimikado added.

Touma glared at him and tried to say something but the full mouth made it into gibberish.

With his usual smirk, the damn bastard leaned in, hand at his ear. "What was that?"

Touma swallowed and washed it down with some soda, then grumbled, "If not for your dirty tricks, we would have won."

"Hey, I didn't break any rules."

Fukiyose frowned and, next to her, Himegami gave Tsuchimikado a displeased look. But neither argued.

"It's not my fault this idiot here is so easily swayed," Tsuchimikado said nodding at Aogami. "Or you, Kami-yan."

That smug grin of his was so annoying… However, he wasn't wrong. No powers or spells were involved. The only one to blame for Aogami so happily turning into a trampoline for Fukiyose was Aogami himself. Same went for Touma. He had frozen like deer in the headlights just because of a few silly words. About Mikoto again. Calling her his girlfriend… seriously, some people would go with the same gag for ages…

But then he remembered the whole question.

Bought a return gift for you girlfriend yet?

The burger almost slipped out his hands. White day was in three days and he had no idea what to get Mikoto. He hadn't even thought about that, because of the coming exams, as well as her stupid bet. What would even be considered appropriate? Or good? For a boy with zero experience, it was quite frankly a difficult matter to decide.

Thankfully, he wasn't alone. Though some characters here were… questionable. Still, he made his shot.

"Hey… what do you think would be a good White day gift?"

"Now this is a strange change of topic," Tsuchimikado said, dipping a fry in sauce. "Trying to pry what to get Maika?" he asked and pointed the fry at Touma. "Cheeky."

Just as he finished, Fukiyose said. "Kamijou, if it's for me, you don't need to bother. It's not like that energy bar counted as Valentine's chocolate."

Oh, right, there were those too. And also Little Misaka's chocolate. However, it was only Mikoto that was wrecking his head, as usual.

"Actually, it's… for someone else…" he confessed.

All four peered at him, and Aogami flashed a dumb smile. "Don't tell me… is it for a certain feisty lady from Tokiwadai?"

Fidgeting from their stares, Touma looked away. "Mhm," he mumbled loudly sucking soda through the straw.

"Is that really such a problem? Just get her something she would like," Fukiyose said.

"And if I don't know what she would like?"

The staring intensified, their faces practically saying "Seriously?". Even Himegami's blank expression broke in surprise.

"Wh-what? I told you, we aren't dating or anything. If we ever meet it's only by pure coincidence and soon after we get dragged into some kind of trouble," Touma said rather annoyed. "Well, I get dragged in and Misaka… just helps me out, for whatever reason. Because she is kind… Honestly, we are barely even friends."

The others exchanged looks, seemingly having some kind of silent discussion. In the end, all four sighed exasperated.

"Traditionally, a return gift is something white, usually sweets," Himegami spoke.

Some white sweets… That would be appropriate. Cheap too. Easy, no hassle at all. Honestly, he already had his plate full with the damn bet. And yet… the idea of giving Mikoto plain white chocolate just didn't sit right with him.

"Uh, such a sour face," Tsuchimikado said.

"Well, this is Tokiwadai we are talking about. It's full of rich girls," Aogami noted. "I hear they even have a princess or two there. Kami-yan's sweetheart might take some cheap white candy as an insult."

Too troubled by his dilemma, Touma didn't even react to "sweetheart". He did, however, tried picturing Mikoto's reaction. Would she be angry? Well, it certainly didn't take much to set that girl off. For him, at least. But she didn't seem like the type that measured gifts by their price.

Fukiyose shook her head. "You guys are making it way too complicated. Kamijou, the number one thing about gifts is the attention. And I don't mean this girl will be head over heels for whatever cheap thing you get her. You need to put some heart into it. There should be significance to your gift."

Significance, huh… Touma thought it over, as if turning an object this way and that way to inspect it. To grasp its purpose. So, the gift should mean something. But what?

"In the first place, a White day gift is a response to the Valentine's chocolate," Himegami offered. "A simple treat for courtesy, something of importance for friendship, and…"

"No "and"! Only those two options. The L-word is out of the question," Touma cut in.

Ever so slightly, Himegami narrowed her eyes, corners of her mouth shifting down but a millimeter. A barely noticeable change, but for those around the table it spoke volumes.

Fukiyose glared daggers at Touma. "Kamijou…"

The burger fell on the plate as he slapped his hands together in apology, head low. "Sorry for interrupting, Himegami! Your insight is very valuable. Please, continue. Just… no… no L-word, ok?" he asked peeking up.

After a few agonizing seconds Himegami's face turned blank again. Though Fukiyose kept on glaring for a while longer.

"There isn't much to add. It all depends on what kind of chocolate a girl gives you. Basically, you reply to her feelings," Himegami said.

"Sounds pretty simple, eh, Kami-yan?" Aogami snickered.

Touma fell back in his seat with a long exasperated sigh. Nothing was simple when it came to Mikoto.

"Such misfortune…"