Hello, everyone! Last chapter saw Mikoto and Touma's reunion after the end of World War 3. We are now finally in New Testament! The new chapter of the Railgun manga just came out, and it was pretty great! Hopefully, I'll be able to incorporate more information about Mikoto's backstory into this fic, thanks to this new Railgun arc.
YoLO1992: Yes, they finally said those words to each other! I was debating between having it happen here or a bit later, and I decided that it would be appropriate for them to state their love for each other after a traumatic experience like this. Yeah, the Daihasei Arc is already over, but Mikoto will tell her friends the truth about it soon, so they will talk about the Level 6 Shift attempt. No, this fic isn't ending, I'm planning to continue it into NT and hopefully GT.
Stryper88: My version of NT2 is in this chapter, so I hope you enjoy it! Saying those words was a key moment for Mikoto, as well as for Touma. Yeah, Shokuhou's reaction to them dating will definitely be fun and interesting to write, I still haven't completely decided when and how it'll happen. You're right, Touma does care a lot about his mother, so perhaps a phone call between them sometime soon would be appropriate. I am planning some slice of life chapters before they go to Hawaii, which will have some nice fluff to separate the more intense chapters. No problem, I really appreciate you pointing out the typos, so that I can fix them.
DBZLEGEND154: No worries, and it's good to see you back. Yep, their relationship will continue to grow in NT, and I'm glad Mikoto's involvement felt natural. There are some scenes in upcoming chapters I've been excited to write for a while now, so I hope you continue to read them.
Toa Solaric: Thanks! I'm glad you enjoyed their reunion.
AnimeMaster24: You'll see what happens in that scene in this chapter. I hope you enjoy it!
Bonsly24: Thanks for keeping up the story, I'm glad you're enjoying it!
GG Vegito: Yeah, it's finally time for NT! Lots of good opportunities for KaMikoto moments are coming up!
fencer29: Indeed, they won't have too long for a break. WW3 ended on October 30, and the Freshman Arc occurs on November 5, so there is actually quite a bit of time in between, though traveling across Russia definitely takes a long time.
Aminadab Brulle: Oh wow, I didn't even know that. Thanks for catching it! Don't worry, I plan to have plenty of Sisters fluff/teasing in NT. Misaka Worst will definitely be appearing soon, and I do want Mikoto to meet Dolly at some point, though I haven't decided on exactly how or when.
Guest10032: Yeah, my version of the Homecoming Arc will be in this chapter. I was a bit worried that I didn't describe Mikoto's despair fully enough, so I'm relieved that you found my description of a broken Mikoto compelling. If Misaka 10777 visits Academy City, she'll definitely want to find some way to differentiate herself. The Railgang learning the truth about the Daihasei Festival, or at least the Science Side part of the truth, will indeed be the first part of their appearance in NT. I'm not completely sure what I want to do with them, but they might pay a bit more attention to the weird things that happen around the city. Thanks for the correction, I completely forgot about that! I'm happy that that chapter is one of your favorites! Scenes with just the two of them are definitely nice to write, and there'll be plenty of those in the near future.
tython055: Yeah, Mikoto found out that Touma was alive a lot sooner than in canon, but it was still enough time for her to break down into despair. Touma restoring their memories will definitely be a major change, and Shokuhou will definitely be upset about it, though I don't think it would be because of harm to Touma, since this doesn't really harm him at all. It might take Shokuhou a while to learn about this, though if Kuroko starts acting suspiciously around her, Shokuhou might immediately read her mind and find out. The new Railgun arc with Mikoto's backstory is definitely very interesting, and I hope I'll be able to incorporate some of that into my fic, though it might be hard to have Mikoto's previous roommate appear, since I may not know what happened to her until the end of the arc. Her manipulating the cliques into destroying each other is an intriguing theory, but I don't want to assume it or any other theory before it's actually shown in canon. But you're right, it could definitely give some good material for Railgun-side stories in this fic.
xellos540: Yeah, it was a very sad scene for Mikoto. I didn't know they met before either, but Aminadab Brulle pointed it out in their review, so I edited that part. Itsuwa and Kanzaki knew about Touma's girlfriend, so the news soon reached Birdway. It's probably too soon for Birdway to be jealous, since her big moments with Touma were in NT5 and NT6. No, Mikoto had to wait until he returned to Academy City 6 days later, even though his phone survived in canon. I don't think he called Mikoto or anyone else. We could assume that either he had a card that could work for payment, or Birdway gave him some money. Yeah, Touma knew he couldn't completely promise to never make her worry like that. He will have to remember to apologize to Index. He already talked to Vento after that fight, and he doesn't yet know that Accelerator helped out in the end. Indeed, WW3 did have that one good effect. Basically, Index sang a song to cure a virus in Last Order's brain during the Academy City Invasion arc, and Accelerator sang that song again when Last Order was infected with a virus again. Misaka 10777 is pretty happy with the indirect compliment and the necklace. It's unclear if Touma really knew more before his memory loss, so maybe he has something besides the dragons and the invisible thing. Shokuhou will indeed be involved soon, though not quite yet.
Streetmud: I'm glad you enjoyed their earlier reunion. I was a bit worried that people would prefer them to reunite at the same time as in canon, so I'm glad that this version of their reunion had a good reaction. I would recommend you start reading NT, since I won't be writing the full details of every single fight, and it'll give you context for seeing where I change the story and where I keep it the same. I'm glad you enjoyed those cute moments, I wanted them to counteract the sad scenes in the earlier part of the chapter.
HunterX097: I'm glad you enjoyed their reunion. It'll definitely be interesting to see the Railgang's reactions to the Level 6 shift attempt on Mikoto and to Touma's dragons.
The One who saw All: Yeah, I saw that quite a few people were interested in seeing Mikoto fall into depression, and how her friends would react to Touma's death and Mikoto's depression. But I didn't want Mikoto to suffer for as long as she did in canon, and since his phone was confirmed to have survived in canon, I figured that he would call Mikoto as soon as possible in this case. Mikoto will probably tell her friends about Touma almost dying, so we'll get to see how they react to that. In any case, I'm glad you still enjoyed the chapter.
Touma had been back in Academy City for a couple of days. As soon as he'd reached home, he had bowed to Index and apologized to her again for lying about his memory loss. At first, she'd taken it surprisingly well. But then he'd let it slip that Mikoto had known about his memory loss for a few weeks, which had made Index really angry. He'd tried explaining that Mikoto had found out on her own, but that hadn't stopped Index from painfully biting down on his head. This had confirmed to Touma that his misfortune was still with him.
Now, the boy had just finished defeating the Freshman, along with Accelerator and Hamazura, and saving a girl named Fremea Seivelun. Birdway and her subordinates had also appeared soon afterwards.
The three boys were now exchanging phone numbers, and Hamazura noticed the strap on Touma's phone. He asked, "Hey, what kind of phone strap is that?"
Touma glanced at it and answered, "Oh, it's called Gekota. I got it as a gift from my girlfriend."
Hamazura raised his eyebrows, "Oh, you have a girlfriend too? Congratulations!" He was really happy with Takitsubo, who he had gone all the way to Russia to protect, so he figured that the other boy was also just as fortunate.
Accelerator then noted, "Oh, so you're dating the third-rate, huh?" Now that he thought about it, he realized that Touma and Mikoto had probably been on a date at that amusement park a few weeks earlier.
Hamazura then suggested, "We all just came back home from Russia, right? How about we get some drinks to celebrate?"
Birdway pointed at Touma's face and replied, "I don't mind taking a detour, but after that we can head to his place to sit down and talk about the other side of the world, besides the Science Side." She had earlier told them that a new enemy was emerging after World War 3, which Academy City was preparing to fight. She now wanted to brief the three boys, all of whom had been involved in that war.
Touma, Accelerator, and Hamazura all agreed, so they all set off in search of a place to get some alcohol.
Meanwhile, Mikoto was taking a nighttime walk along a nearby street. She and Touma had just arrived back in Academy City a few days earlier, and she was really glad to be home again. When she'd arrived back home, Kuroko had been ecstatic to see her, and Mikoto had told her that she'd caught up to Touma in Russia. Kuroko had asked for more details, but Mikoto had promised to reveal more the next time they hung out with Saten and Uiharu, which would hopefully be soon.
Suddenly, she heard a voice say, "Heyyyy, is that you, Miko-chan?" Mikoto looked over and saw her boyfriend a few meters away. He had a tie wrapped around his head, he was carrying a box of sushi by a string, and he was drunkenly staggering towards her.
Mikoto was absolutely confused. "Touma? What happened to you, why are you drunk?" She wasn't sure how to react to that new nickname, so she focused on the more important issue.
Touma came a bit closer and handed her the sushi box, "Here, Miko-chan, this is a present for you!"
The girl was dumbfounded as she looked at the item now in her hands, "This is not a present! It's just some normal sushi!"
The boy then said, "Nyaa nyaa."
Mikoto facepalmed and muttered, "I can't follow what you're saying, and now you're not even speaking in a human language. You're even worse than Mama when she gets drunk!"
Touma then suddenly embraced her and exclaimed, "I love you so much, Miko-chan!"
The girl blushed at that sudden action, but she wrapped her arms around him and gently combed her fingers through his hair, sighing, "I love you too, Touma." Mikoto noticed that he was relaxing in her arms, so she hoped he would start sobering up soon.
Suddenly, four identical-looking girls wearing goggles and necklaces approached the couple. Mikoto's eyes widened as she saw her sisters, and she asked "What are you guys all doing out here?" She knew that usually only one of them would go out at a time, so she was surprised to see all four of them out together.
Before any of them could reply, Touma abruptly extricated himself from Mikoto's arms and stumbled towards the Sisters. He pulled one of them into a hug and said, "Helloooo, 10032-chan!"
Misaka 10032 was startled and stepped back a bit, but soon hugged him back. "We learned that the boy was back in Academy City, so we wanted to try finding him, says Misaka 10032, answering Big Sister's earlier question. Misaka is surprised that you were able to deduce her identity while intoxicated, says Misaka 10032 to the boy, feeling extremely pleased."
The boy then grabbed onto her shoulders and stood back a bit, replying, "Of course! You're the one with the pretty heart necklace, 10032-chan!"
"Misaka is happy to see you again after your apparent death, says Misaka 10032."
Touma let go of her and replied, "No worries, a little bit of cold water was no match for me!"
Mikoto rolled her eyes and muttered, "You had to be rescued from that cold water, you idiot!"
The boy then hugged the girl with the snowflake necklace and explained, "Hiii, 19090-chan! Ooh, you're the one with the highest serial number! How are you doing?"
"Mi-Misaka is really glad that you're alive, says Misaka 19090 as she hugs you back. She was really sad when she thought you might be dead."
The boy squeezed her a bit tighter and rubbed her back, "Aww, I'm really sorry, 19090-chan. I hope you can forgive me."
"M-Misaka forgives you, since you came back alive in the end, replies Misaka, feeling comforted in your arms." The two of them stayed like that for a bit longer.
After Touma let go of Misaka 19090, he moved on to the girl with a flower necklace. He wrapped his arms around her waist and said, "Heyyy, 13577-chan! Oh wow, all the digits in your serial number are odd. What are the chances of that?"
"Out of the 9970 living Misakas with a serial number, including Last Order, only 625 Misakas have that property, calculates Misaka as she returns your embrace. That's an approximately 6.27% chance, or just over 1 in 16, concludes Misaka 13577, answering your whimsical question. If you include the dead Misakas, there are 1405 Misakas out of 20001 with that property, which is an approximately 7.02% chance, or just under 1 in 14. By the way, Misaka's serial number is also prime, adds Misaka 13577, stating an additional fact."
Touma let out an exaggerated sigh, "You're so much better at math than me, 13577-chan!"
"Well, she does have access to the Misaka Network, begins Misaka 10032. But that's actually quite a simple math problem, even for a high schooler with access to just one brain, adds Misaka 10032, playfully mocking you."
Mikoto chuckled at the scene in front of her, knowing that this was the kind of peaceful life she'd been hoping to return to after the war.
The boy released Misaka 13577 and finally hugged the girl with the star necklace, exclaiming, "Last but not least, it's you, 10039-chan!"
Misaka 10039 wrapped her arms around Touma's back. "Welcome back to Academy City, kindly says Misaka 10039 while patting your back. Big Sister, do you know why the boy is drunk?"
Mikoto shook her head and shrugged, "No, I just ran into him a few minutes ago, and he was already like that!"
"He hasn't ever gotten drunk before, right, asks Misaka 13577. Perhaps he's celebrating his return from Russia, suggests Misaka 13577."
Mikoto replied, "Yeah, that could be it." She then noticed that her boyfriend had separated from Misaka 10039 and was now swaying on his feet. She quickly walked up to him and wrapped her left arm around his right arm to support him, sighing, "All right, you idiot, I'll walk you home, okay?"
Touma grinned at her, "Okay, Biri-Biri!" He instinctively leaned against his girlfriend, and began walking alongside her.
"All right, Big Sister, it was nice seeing you and the boy again, but we'll be returning to the hospital now, reports Misaka 10032. Please take care of the boy, requests Misaka 10032."
Mikoto waved at her sisters with her free hand, "Sure, good night, guys!" Her four sisters then began returning to their home, and Mikoto now prepared to return her boyfriend to his own home.
The entire time, Accelerator, Hamazura, and Birdway had been watching as those five identical girls gathered around Touma, who had given every single one of them a hug. They couldn't hear what that boy and the girls were saying, but the sight itself presented enough of a spectacle.
Accelerator muttered with some exasperation, "Well, at least we don't have to be the ones to deal with his drunk ass anymore." Although he and Hamazura had also had some drinks, they had remained sober, and having to deal with a drunk Touma hadn't been a pleasant experience. Nonetheless, Accelerator did admire that boy for having another side to his life rather than just fighting, and for being able to let his peaceful and violent sides coexist.
Birdway was mostly astounded at the sight of five identical girls, and mused, "So, that boy's girlfriend is a quintuplet, huh?" She didn't know that the Misaka Sisters were clones, so that was the only logical conclusion for her.
On the other hand, Hamazura had heard from Mugino that military clones of the 3rd Ranked Level 5 had been created, so he wasn't as shocked to see so many identical girls. He was a little surprised to see them all out at once, though, since their existence was supposed to be a secret. But most of all, he was extremely impressed with Touma for not only having the Railgun as his girlfriend, but also for being allowed to get cozy with her clones too. He shuddered thinking about the beatings he'd get if he ever tried hugging Mugino or Kinuhata. Hamazura then mused out loud, "I should ask him to teach me his ways."
Somewhere else in the city, Hamazura's girlfriend Takitsubo was eating a corn dog she had bought from a convenience store. Her normally tired eyes widened as she suddenly felt a bad omen, and she exclaimed, "Hamazura's heading down an evil path!"
Soon afterwards, Mikoto and Touma joined up with Birdway, Accelerator, and Hamazura right in front of Touma's dorm. Touma was starting to sober up, but he was still leaning against Mikoto. Mikoto glanced at Accelerator and said, "Oh, it's you."
Accelerator scoffed, "Oh great, I have to deal with you too?" If Mikoto was going to join them, it would be a very awkward meeting.
Mikoto then looked at Birdway and Hamazura and asked her boyfriend, "Who are these two?"
Touma pointed at the small girl and said, "That's Birdway, she's the one who rescued me from the Arctic." He then pointed at the blond boy and continued, without hesitation, "That's Hamazura, he's the one that captured your mother."
Mikoto glared at Hamazura and seethed, "Oh, really? That was you?" Although she was holding onto Touma's right arm, his hand wasn't touching her, so she began sparking, causing Hamazura to flinch.
Hamazura tried placating the furious girl, "I'm sorry, it was a stupid assignment I took when I was in charge of Skill-Out!" Although he had defeated Mugino multiple times, he wasn't sure about his chances against Mikoto.
Touma then suddenly grabbed onto Mikoto's hand and squeezed it, making her sparks disappear. He said, "It's okay, Biri-Biri, I punched him really hard in the face, so he's a good guy now."
Mikoto couldn't help but laugh at his nonchalant tone. He made it sound like his punches had the power to turn villains into good people, but she realized that this was perhaps true, in a way. In any case, she knew that Touma had saved her mother, so Mikoto supposed that Hamazura had received enough punishment. She turned back to Birdway and bowed to her, "Thank you so much for saving Touma! I don't know what I would've done if he'd died!"
Birdway smirked and replied, "No need to thank me, I did it because we still need that special right hand of his. But now that we're all acquainted, let's go inside and talk about the current situation."
Mikoto wasn't quite sure what Birdway was referring to, but she figured that there was some new magic-related threat emerging. She and the rest of them entered Touma's dorm room, where they, along with Index, would receive a lecture from Birdway.
A while later, Touma and Mikoto were standing alone on his balcony. Everyone else, other than Index, had just left his dorm. It had been a pretty eventful night. Mikoto had learned about her boyfriend working with Accelerator and Hamazura to defeat the Freshman and save a little girl who seemed a bit familiar for some reason. All of them had then received a lecture on magic from Birdway. Mikoto had felt a bit awkward being around Accelerator and Hamazura, but she'd been calmed by the presence of her boyfriend, who'd sat next to her. Birdway had covered a lot of the stuff that Index had already taught Mikoto, but she had also covered magic cabals and ley lines, which were new topics for Mikoto.
The lecture had been interrupted when a giant structure known as the Radiosonde Castle had appeared in the sky. It had apparently been tracking Touma's Imagine Breaker, and it had threatened to fall down onto the city. To stop that, they'd had to destroy a magical transmitter which Accelerator had identified as being in District 7's Central Hub Transformer Station. Touma and Mikoto had gone to that location, but once they'd gotten inside, it turned out that the transmitter was buried under a thick concrete floor. Mikoto had used her railgun to drill a hole in the concrete, and Touma had destroyed the transmitter with his right hand. As a result, the Radiosonde Castle had fallen harmlessly into the Pacific.
After that situation had been solved, Birdway had finally revealed the name of the new enemy, GREMLIN, which fittingly symbolized the Magic Side damaging the Science Side. Apparently, they were planning to strike soon in Hawaii.
Mikoto turned to her boyfriend and asked, "So, you're really going to Hawaii, huh?"
Touma continued looking forward and answered, "Yeah. Like I told Birdway earlier, I don't really have a choice, since they're coming for me anyway. Plus, maybe I'll be able to learn some more about the real truth behind my Imagine Breaker." He held up his right hand and gazed at it as he said this.
The girl leaned back on the railing and replied, "Well, this time, I'll be going with you from the beginning! Heck, it might not be so bad, a trip to Hawaii actually sounds pretty nice."
Touma chuckled, "I don't know if we'll have time to do any touristy things there. But I'm glad you'll be by my side this time. You're much better company than Lessar."
Mikoto nudged his shoulder and retorted, "I would certainly hope so!"
The boy then frowned and noted, "I already missed a lot of time in school while I was in London and in Russia, and now I have tests coming up in a few days! At this rate, I won't be able to save my grades!"
The girl smirked and suggested, "Then how about a study date tomorrow? I can help you prepare for your tests!" Touma had been open to being tutored by her the last time she'd brought this up, so Mikoto figured now was the perfect time to offer.
Touma's sharply turned to her with widened eyes, "Really? You'll do that for me?"
Mikoto nodded, "Of course! You don't deserve to fail your classes because you're too busy saving the world."
The boy gave her a wide grin and suddenly pulled her into a hug, exclaiming, "Thanks, Biri-Biri! I love you so much!" Touma knew that she'd be able to help him a lot, given just how smart she was, and any time he got to spend with his girlfriend was a plus.
The girl's cheeks reddened, but she slowly wrapped her arms around his back and replied, "Love you too, Touma." Although they would soon have to charge into another battle, Mikoto was glad that they still had some time to spend together.
The next evening, Touma was waiting for his girlfriend to arrive for their study date. He and Index had just finished dinner, so he set about gathering all his study materials while he waited.
It wasn't long before he heard a knock on the door. When he got up and opened it, he saw Mikoto, who wasn't dressed in her usual uniform. Instead, she was wearing a purple and white hoodie and shorts, and she was also carrying a shopping bag. After letting her in, he immediately wrapped his arms around her waist and hugged her tightly, greeting her "Hey, Biri-Biri!"
Mikoto returned his hug and replied, "Hey, Touma!" She then planted a brief kiss on his lips.
They pulled apart a bit, but Touma still had his hands on her waist and was absent-mindedly rubbing her hoodie with his thumbs. He gave her a smile and said, "That's a really cozy-looking outfit!"
His girlfriend smirked back at him and revealed, "Yeah, actually, this is the outfit I wore that night I fought against that Doppelganger! I figured I'd wear it instead of my uniform for a change in pace."
Touma then teased her, "I see, so it's something you wear when you're breaking into somewhere and being a bad girl. And you're even breaking curfew right now, aren't you?"
Mikoto blushed and lightly punched him in the shoulder, "Sh-shut up! I'm not a bad girl! And you were the one who chose this time, you idiot!"
The boy chuckled, "Yeah, you got me there. Thanks for coming, you're a big lifesaver!" The two of them then entered the living room and sat down next to each other under the kotatsu. As she set the shopping bag on the table, he asked, "What's in that bag?"
Mikoto pulled out a bunch of melon buns and said, "I bought these study snacks on the way here." She turned to the other girl in the room and added, "You can have some too, Index!"
Index immediately leaped towards the table and grabbed about half of the buns for herself. She then sat down a bit away from the table, so as not to disturb their studying. As she began gobbling them down, she said, "Thank you, Mikoto!"
Mikoto smiled at her and replied, "You're welcome!" She was pleasantly surprised that some food was all it took for Index to at least temporarily call her by name.
A certain urge came over Touma as he gazed at his girlfriend. He brought up both of his hands and gently pulled Mikoto's hood over her head. When she looked at him in confusion, he began rubbing the top of the hood, cooing, "You're so cute!"
The girl blushed, but let him continue for a few moments, since he was making her feel nice and warm. But then she gently pushed his arm away and pulled her hood back down, chiding him, "Come on, we're here to study, right?"
Touma chuckled, "Yeah, you're right, Mikoto-sensei." He felt warm sitting right next to her, with their shoulders and legs touching, but he knew he had to focus on studying.
Index felt a bit depressed as she looked at the couple. She had mostly accepted their relationship, and she could see that Mikoto made Touma really happy. However, it still hurt a little, and she felt like a third wheel in her own home. Index supposed she'd just have to get used to it.
Mikoto and Touma each began eating a melon bun. She turned to him and asked, "So, what do you want to go over first?"
Touma opened one of the textbooks on the table, "I have a biology test and a history test tomorrow, so how about biology first? We've been covering the nervous system in class, and I'm a bit confused on how neuron signaling works."
Mikoto grinned with excitement, "Ooh, that's a fun topic! So for that you need to know about neurotransmitters and action potentials. Do you know anything about those?" She knew quite a bit about this subject due to her interest in bioelectricity.
Touma nervously rubbed his head and admitted, "Not that much. I know that neurons signal to each other using neurotransmitters and that the signals somehow travel using electricity."
The girl nodded, "Yeah, that's the basic gist of it, but you probably need to know some more details. You know what an electric potential difference is, right?"
The boy replied, "Yeah, I think so. It's when there's a difference in electric charge between two locations, right?"
Mikoto winced a bit but replied, "Well, that's not completely accurate, but I guess that's close enough for our purposes." She held out her hands with her index fingers pointing horizontally, with one above the other. She then created some sparks between her fingers and said, "See how the sparks are moving from the top finger to the bottom? I did that by concentrating a negative charge on the top finger and a positive charge on my bottom finger. This potential difference causes the sparks to move downwards."
Touma nodded in understanding, "Right, that's because your sparks are made of electrons, so they want to move towards the positively charged surface."
Mikoto nudged his shoulder and praised, "Good, that's right!" She flipped through his textbook until she found a specific image, and pointed at it as she explained, "So normally, neurons have a potential difference between the inside and the outside of the cell. A major part of this is due to the sodium-potassium pump, which uses energy to pump 3 sodium ions out of the cell and 2 potassium ions into the cell at a time. So what do you think happens when this pump keeps running over time?"
Touma rested his head on his fist and replied, "Well, if it keeps pumping sodium out and potassium in, then eventually there'll be a lot more sodium on the outside than the inside, and vice-versa for potassium. And I guess if 3 positive ions are leaving while only 2 are entering, then the outside of the cell will become positively charged, and the inside will become negatively charged."
Mikoto excitedly nodded, "That's exactly right! So because of this, there's a normal resting potential of about -70 millivolts." Pointing again at the image in the textbook, she continued, "Now, the membrane also has sodium channels and potassium channels, which let those ions flow through when they're open. What would happen to the membrane potential if the sodium channels opened up?"
The boy thought for a bit and soon answered, "Well, the sodium ions will want to flow from the side with higher concentration to the side with lower concentration, right? So they'll flow back into the cell, especially since the inside is more negatively charged." But he then wondered, "But what about if the potassium channels open? I would think that the potassium ions would flow out of the cell because of the concentration gradient, but the outside is positively charged."
Mikoto nodded, "Yeah, you're right that the concentration difference and the electric potential difference have opposite effects, so there'll be some equilibrium point where potassium will stop flowing out of the cell. But during an action potential, the sodium channels are the ones that open first, which lets sodium ions flow in and make the membrane potential more positive." As she said this, she traced her finger along a graph showing how the membrane potential increased from -70 millivolts to +40 millivolts during this process. She added, "This is called depolarization, and it results in a positive feedback loop, since increasing the membrane potential also causes more sodium channels to open."
Touma mostly understood what she was telling him, but asked, "I get that once the sodium channels start to open, there's a positive feedback loop that keeps it going, but how does it start in the first place?"
The girl pointed to a picture of a neuron and answered, "It all starts when a neurotransmitter binds to a dendrite at one end of the neuron. This is what initially causes the sodium channels to open. And because increasing the membrane potential opens more nearby sodium channels, this signal can eventually propagate across the neuron."
Touma nodded, "Okay, that makes sense." Pointing to the graph from earlier, he asked, "So after the membrane potential reaches this peak, how does it go back down? Is it the potassium channels?"
Mikoto excitedly replied, "Good, you're getting it now! Yes, once depolarization reaches a peak, the sodium channels close and the potassium channels open. And now that the inside of the cell is positively charged, there's nothing stopping the potassium ions from flowing out of the cell." Pointing at the graph again, she explained, "This repolarizes the membrane potential again, even below the resting potential, so it's called hyperpolarization. And at this point, the potassium channels close too, and the sodium-potassium pump restores the original resting potential."
The boy carefully listened to her explanation while watching her point to the graph. He replied, "Okay, I think I understand. So each step, both depolarization and repolarization, propagates along the neuron, right? And I guess when the signal reaches the end of the axon, neurotransmitters are released to signal to the next neuron?"
The girl replied, "Exactly! But it doesn't have to be another neuron, the neurotransmitter can also signal to a muscle cell. The muscle cells will then undergo their own action potentials, which eventually leads to muscle contraction."
Touma then mused, "Huh, so in the end, muscles are controlled by electrical signals. Does that mean you could control other people's muscles with your ability?"
Mikoto was a bit surprised by his question, but she answered, "Theoretically, yes, but it would require very precise control unless I wanted to just destroy their nerves and muscles. Those scientists who originally took my DNA map said they could perhaps use my ability to cure muscular dystrophy, but you know how that turned out. I can control my own muscles with my ability, though."
Touma nodded and recalled, "Right, you can boost your own strength with your ability, though you're still pretty strong even without it."
Mikoto replied, "Yeah, that's right. And I haven't actually tested this yet, but I'm pretty sure I could use my ability to move myself even if I were injected with a paralysis drug."
The boy's eyes widened, "Wait, really?" He didn't really know how paralysis drugs worked, but he was surprised to hear that she could overcome them.
The girl nodded, "Yeah, they usually work by stopping neurotransmitters from working, but I could use my ability to force action potentials to happen in my neurons and muscle cells even without any signals from neurotransmitters. It would take a lot of energy, though."
Touma chuckled, "Yeah, and hopefully you won't ever have to do that." He hoped his girlfriend would never be put in such a vulnerable situation. He then leaned back and continued, "Man, you didn't even need to skim the textbook, did you? You just knew all of that off the top of your head."
Mikoto smirked at him, "Well, this is a pretty basic topic in neurobiology." She gave him a quick kiss and then ruffled his hair, saying, "But you were a pretty good student! If you didn't have to skip class so often, you'd probably get decent grades."
The boy sighed, "Well, it looks like that's not going to stop happening any time soon. Anyway, I think that's good enough for my biology test, so how about we move on to history?"
Mikoto stretched her arms above her head and replied, "Sure, so what do you need to go over for that test?"
Touma closed the biology textbook and opened his history textbook, answering, "I missed a bunch of classes where we covered the history of Japan in World War 2, so I need to brush up on that."
The girl casually flipped through the textbook and mused, "Okay, so you don't need to focus on the European theater, just the Pacific theater. That makes it a bit easier. What do you know already?"
The boy scratched his head and tried to recall all he'd learned on that subject, "Um, I just know some of the main events. I think Japan was already at war with China, and at some point, the US stopped selling oil to Japan, so the Japanese decided to attack the Western powers to conquer their colonies with oil and other resources. They launched a surprise attack on Pearl Harbor and then conquered those colonies in the first few months, but then they lost the Battle of Midway. After that, the US kept building a lot of warships and pushed back across the Pacific, and eventually Japan surrendered after the US dropped atomic bombs on Hiroshima and Nagasaki and the Soviets entered the war."
Mikoto smiled at him and rubbed his knee, "Good, you know pretty much all of the basics. Let's start with what led up to the war. After World War 1, the US and Japan were the main powers in the Pacific region, and they were competing for influence in China. Japan had actually been allied with Britain during World War 1, but the British dropped the alliance because the US didn't like it, and some of its dominions didn't want to get dragged into a war against the US."
Touma knew that Japan had fought in World War 1 on the same side as Britain, but he was a bit surprised that they'd had a formal alliance. He then replied, "Okay, so the British basically chose the US over Japan, right? And what do you mean by dominion?"
Mikoto nodded, "Yeah, the British didn't make a formal alliance with the Americans, but they still chose to abandon Japan to keep good relations with the US, which made sense, since the US was the much stronger power. A dominion was a country that was mostly independent but still sort of part of the British Empire. I think the main ones were Canada, Australia, New Zealand, and South Africa."
The boy leaned his head on his hand and said, "Huh, I didn't even know that was a thing. So how did Japan end up invading China before the main war even started?"
The girl then turned to a map of the Pacific region and pointed at a certain location, "Well, first they conquered Manchuria in 1931, which is this region in northeast China. The Chinese were in the middle of a civil war between the Nationalists and Communists, so there wasn't much resistance. And then in 1937, Japan invaded the rest of China, and they basically conquered all the major cities on the coast, including Beijing, Shanghai, and Guangzhou, but the Chinese retreated into the interior and continued fighting."
Touma then wondered, "Why was Japan just going on this conquest spree in the first place? And is this when the US embargoed Japan?"
Mikoto shook her head, "No, the embargo would come later. The Japanese government had become more and more militaristic in the years before World War 2. There was basically a government by assassination, where officials who weren't militaristic enough got murdered by officers in the army or navy. For example, in the May 15 Incident in 1932, Prime Minister Inukai Tsuyoshi was shot by naval officers, and in the February 26 Incident in 1936, army officers assassinated two former prime ministers and some other officials."
The boy's eyes widened, "Wow, that's crazy, I didn't know at all about that. Was it sort of like the coup in the UK?" He recalled how Carissa had launched her coup because she'd felt that the UK was being weakened in comparison to France.
The girl nodded and explained, "Yeah, a big reason was that Japan had signed naval limitation treaties with the US and the UK which only let the Imperial Japanese Navy build 3/5 the amount of battleships and aircraft carriers as the US Navy or the British Royal Navy, with a similar ratio for smaller warships. Those militant officers thought that this weakened Japan too much."
Touma then reasoned, "Hmm, that ratio does seem unfair. But the Americans and British had the strongest navies anyway, right?" If so, it would make sense that they wouldn't want Japan to suddenly have an equally large navy.
Mikoto replied, "That's true, and it's largely because they had to split their navies. The US Navy was split between the Pacific and the Atlantic, while the Royal Navy had fleets all over the world, though mainly in the North Atlantic and the Mediterannean. Meanwhile, the Imperial Japanese Navy could concentrate its entire force in the Pacific. But there was the worry that if Japan went to war against the US, they wouldn't be able to defeat the American Pacific Fleet before it was reinforced by their Atlantic Fleet."
The boy wasn't sure how valid that reasoning was, but realized that enough people had believed in it that the Japanese government had been forced to become more militaristic. He then asked, "Okay, so I know that Japan went to war because of the oil embargo, but why did the US place that embargo in the first place, if it wasn't because of the invasion of China?"
The girl pointed to the map and answered, "It happened when Japan occupied all of French Indochina, which was possible because France had already been conquered by Nazi Germany. This threatened the British and Dutch colonies nearby, so the Americans froze all Japanese assets and stopped selling oil and other resources to Japan, and the British and Dutch followed suit. The US actually produced most of the world's oil back then, but the British also controlled a lot of oil in the Middle East and Dutch also had a lot in the East Indies. Japan became cut off from buying any of this oil."
Touma immediately deduced, "And that meant that Japan didn't have enough resources to continue their war in China, right?"
Mikoto replied, "Yep, and so Japan had the choice of either accepting American demands to withdraw from French Indochina and China, or of going to war against the Western powers and conquering the resources of Southeast Asia. And of course, the former was not really an option."
The boy looked at the map, which showed the British, Dutch, and American colonies in Southeast Asia, and wondered, "Okay, so if Japan just wanted to conquer the British and Dutch colonies for oil, why did they attack the Americans? Did they really want to conquer the Philippines?"
Mikoto answered, "It wasn't really for the resources, but Japan didn't want to leave themselves vulnerable to an American counterattack from the Philippines, so they decided to conquer it. And since that would require attacking the US anyway, Admiral Yamamoto came up with the plan to attack Pearl Harbor with six aircraft carriers to cripple the American fleet."
Touma knew that this was the point where the Pacific War had started in earnest. He recalled, "So that's when Japan attacked Pearl Harbor and all the colonies in Southeast Asia, right?"
The girl leaned forward a bit, so that she could point at each of the Japanese targets on the map. "That's right, Japan launched its offensive on December 8, 1941, though it was December 7 in Hawaii. At Pearl Harbor, they sunk and damaged a bunch of American battleships. They also attacked the Philippines, the British colonies of Hong Kong and Malaya immediately, and brought Thailand into the war as an ally. Japan was able to conquer all of these places, forcing the British to surrender at Singapore and the Americans at Bataan. Around the same time, Japan conquered pretty much all of the Dutch East Indies, securing the oil there, and they also conquered Burma to cut China off from British India. By May 1942, Japan had conquered all of Southeast Asia and a bunch of islands in the Pacific."
The boy was a bit distracted by the feeling of Mikoto's cheek and her hair brushing against his face as she kept moving, but he tried paying close attention to her explanation. He looked at the map showing the maximum extent of the Japanese conquests and mused, "That's a lot of territory to conquer in just a few months. Didn't they have some weird name for it, the Greater East Asia Co-Prosperity Sphere?"
Mikoto scoffed, "That was the propaganda name, yes. Japan claimed that it was liberating all these territories from Western imperialism, but they just became Japanese colonies instead, with Japan just using them for resource extraction and oppressing their people. And of course, Japan had been invading China, an independent Asian country, committing atrocities like the Rape of Nanjing."
Touma replied in a somber tone, "Yeah, I've heard about that too. Japanese soldiers raped a bunch of women and bayonetted babies. It's sickening."
The girl agreed, "Yeah, unfortunately, there were a lot of atrocities like that during this war."
After a pause, Touma then replied, "Well, after Japan conquered all that territory, that's when the Battle of Midway happened, right?"
Mikoto elaborated, "That's right, Japan wanted to invade Midway and brought most of its fleet, including four aircraft carriers, to help. But the US had actually broken their codes, so they were able to prepare their defense, and they also had the advantage of having radar, which the Japanese didn't have on their ships. The US ended up sinking all four Japanese carriers, while losing only one of their own carriers, so Japan was forced to retreat."
Toums thought about how big a loss that had been, and asked, "This was when aircraft carriers made battleships obsolete, right? Because they could launch air attacks from hundreds of kilometers away, while battleships would have to get really close to the enemy fleet."
Mikoto grinned, "Yeah, you're exactly right! You know, when the Imperial Japanese Navy launched its attack on Pearl Harbor, it had the best aircraft carrier force in the world. The US Navy and the Royal Navy had about the same number of carriers, but neither of them had trained much in using them as a combined force. But now Japan had lost four out of the original six aircraft carriers they'd attacked Pearl Harbor with. This was the turning point of the war, and from then on, the US went on the offensive in the Pacific."
Touma then replied, "Wow, it's insane how quickly things turned around. But I guess it would've happened eventually, since the US could build a lot more ships than Japan."
The girl nodded, "Yeah, in fact, the US built about 20 more aircraft carriers by the end of the war, while Japan only built about 10. For the next three years, the Americans kept capturing islands across the Pacific and coming closer and closer to Japan." She swept her fingers across the Central Pacific as she said this, and then focused on some key locations, "In mid-1944, the Americans captured Guam and the Marianas Islands, which let them attack Japan with strategic bombers. A few months later, they began retaking the Philippines, which allowed American submarines to cut off Japan from the resources in Southeast Asia. And then, in 1945, the Americans captured Iwo Jima and Okinawa, and so they were able to keep bombing Japan's cities and completely blockade it from food and resources from the rest of its empire."
Touma nodded along, since he had already been generally aware of the American drive across the Pacific. However, he wondered, "Did Japan try to fight back against those invasions? They still had some of their navy and air forces, right?"
Mikoto answered, "Yeah, the Japanese did try launching attacks on the American fleets after many of these invasions, but the Americans always wiped them out, so by the middle of 1945, the Japanese Navy had been almost completely destroyed."
The boy reasoned, "That's not surprising, since the US Navy probably outnumbered the Japanese navy by a lot. And I guess that's why Japan became desperate enough to use kamikaze attacks?"
Mikoto replied, "Honestly, by that point, kamikaze attacks were only a bit more suicidal than conventional air attacks, since the American fleet had so many aircraft defending it. If you think about it, kamikazes are basically like guided missiles, using human eyes for targeting instead of radar. They were actually pretty effective, damaging lots of American ships, including aircraft carriers."
Touma's eyes widened as he thought about her analogy, "Wow, I never thought about it that way, but you're right, they are like guided missiles! I didn't know they were so destructive!" He then remembered the United States wasn't the only Japanese enemy and asked, "So what were the British doing during this time? They still had control of India, right? And what about China?"
Mikoto turned the page to another map and replied, "The British still had control of India, but they were focused on fighting in Europe and North Africa. It wasn't until 1944 that they really went on the offensive in Asia. Japan tried invading India in 1944, but they were defeated by British and Indian forces, and then the British recaptured most of Burma in 1945. And I think the Royal Navy also sent a fleet to help in the invasion of Okinawa."
After a pause, she pointed at another map and continued, "The Chinese front was mostly stable until 1944, when Japan launched Operation Ichi-Go to take more land in southern China. It was a success, but it didn't really matter that much, since Japan was still losing ground to the US. Plus, the Chinese were able to go on the offensive in 1945 and retake some of their land."
The boy admitted, "Wow, I'm surprised it took so long, but I guess the British and Chinese played a minor role in the Pacific War compared to the Americans."
The girl nodded, "Yeah, the US definitely played the major role. Anyway, by mid-1945, Germany had been defeated, and the US was making plans to invade Japan itself. But because of the kamikazes and the fierce fighting on Iwo Jima and Okinawa, they were very worried about the casualties they would take. Since Japan still refused to unconditionally surrender, the US dropped the atomic bombs on Hiroshima and Nagasaki."
Touma frowned and questioned, "Were those really necessary, though? I sort of get why the Americans thought they were, but so many innocent civilians died because of those bombs."
Mikoto leaned back and sighed, "Yeah, that's true. But even after both bombs were dropped and after the Soviets declared war on Japan and invaded Manchuria, the Japanese Supreme War Council was still split over whether to surrender, so Emperor Hirohito had to break the deadlock."
Touma pondered for a bit and concluded, "Well, it's probably good that Japan surrendered then, instead of prolonging the war any further. The Americans then occupied Japan for a few years, right?"
The girl nodded, "That's right, and they decided to let the Emperor keep his throne to prevent any unrest. And because Tokyo had been heavily damaged by the American bombing campaign, it was ripe for rebuilding, which is how Academy City was created. The US mostly withdrew from Japan after a few years, but they still have military bases in the country. Most of them are in Okinawa, but they also have an entire fleet based in Yokosuka and some other bases scattered around Japan."
The boy placed his hands behind his head and mused, "So Academy City was only created because of World War 2, huh? I guess that war had a lot of big impacts throughout the world."
Mikoto chuckled, "That's an understatement. The Soviets invading Manchuria helped the Chinese Communists win their civil war, and it's why Korea is still split today. But on the other hand, all the Western colonies that Japan occupied soon gained independence, as did India. So I guess that's one good thing that came out of that awful war."
Touma's eyes widened, "Wow, even India? So the British lost a lot of territory after the war despite being on the winning side?"
The girl nodded, "Yeah, the British Empire was the largest in history, but they were too exhausted from World War 2 to hold onto it, so almost all of their colonies gained independence by the end of the 1900's. But they do still have some influence in their former colonies, due to the British Commonwealth."
Touma then chuckled and replied, "Well, in any case, I'm glad that World War 3 only lasted 11 days instead of 6 years, and that there weren't too many casualties."
Mikoto smiled at him and nudged his shoulder, "Yeah, all thanks to you! You know, it's pretty ironic that GREMLIN is launching another invasion of Hawaii soon. Hmm, speaking of our trip there, if we have some free time, maybe we could visit Pearl Harbor!"
Touma smiled back at her, "Yeah, maybe, though I don't know if we'll have much free time." He then wrapped his arm around her shoulders and pulled her closer. He kissed his girlfriend on the cheek and softly said, "Thank you for tutoring me, Mikoto-sensei! I think I might actually have a chance of passing those tests tomorrow!"
Mikoto smiled at him and said, "You'll do fine, Touma!" She then pulled her lower legs out of the kotatsu and placed them under her thighs, sitting in a kneeling position. She patted her lap and offered, "Since you were such a good student, here's your reward!"
Touma blushed at her offer of a lap pillow. Needing no further encouragement, he slid his body further into the kotatsu and laid his down in her lap, enjoying the soft feeling of her thighs. As she combed the fingers of one hand through his hair, he gently grabbed onto her other hand and played with the sleeve of her hoodie. Touma let out a relaxed sigh and closed his eyes in contentment, while Mikoto gazed down at him with a loving smile.
Index had remained silent as the two of them had been studying. But now, she pouted as she watched this display, asking Mikoto, "Do you really have to spoil him so much? You're treating him like a king!"
Mikoto continued looking down at her boyfriend and simply answered, "I think he deserves to be spoiled a little after all the trouble he goes through all the time. Don't you agree?" After all he'd just come back from ending World War 3, and he would soon have to go to Hawaii to fight in another battle. She felt that he needed all the relaxation he could get.
Index sighed and reluctantly admitted, "Yeah, maybe." She also knew that the boy would be getting into another fight soon, but for some reason she felt a bit conflicted about seeing him so happy.
Mikoto and Touma continued enjoying each other's presence for a while longer. Although they would be heading to Hawaii soon, they hoped to make the most of the time until then.