The eighth arc of A Certain Magical Index, consisting of volume 8 of the light novels, chapters 58-65 of the manga, and episodes 6-7 of the anime's second season.
Note: The light novel version begins with Shirai Kuroko having an official test of her abilities on the Tokiwadai Middle School grounds. The test establishes that she can teleport a maximum of 130.7 kilograms in mass and a maximum of 81.5 meters in distance. She runs into Mitsuko Kongou, a Level 4 with the ability Aero Hand, which allows her to generate wind from her hands to launch projectiles at high velocities. Mitsuko makes fun of Kuroko's "weak" scores and says that she will soon become the Queen Bee around here with her superior powers. Kuroko warns her not to be too sure about that and points to Mikoto Misaka, who is testing how powerful her Railgun attack is by firing it at the swimming pool, with Kuroko pointing out that the Railgun is so powerful that they are running out of targets that won't get annihilated by it besides the pool. Mitsuko is amazed by Mikoto's power. This scene is omitted from the anime, but can be seen in A Certain Scientific Railgun, but at a different timeline.
While Touma cooks, Index watches the weather channel. She is amazed and asks how people can predict the weather without magic. Touma explains how rain clouds often form in areas of low pressure, so the weather can be predicted by measuring the air pressure. He gives some of the food he cooked to Sphynx. Index gets angry and bites him, asking why he didn't give food to her first. She calms down and asks why the weather reports have been wrong a lot lately. He says he doesn't know.The reason is because the satellite Tree Diagram (which performed several calculations for Academy City, including weather predictions) was destroyed a while ago, by Index herself, back in the Index arc. A space shuttle flies up, examines the debris of the satellite, and collects a piece of it.In the girl's locker room, Mikoto and Kuroko shower. Mikoto complains that their school has been holding extra P.E. sessions due to the Daihasei Festival coming up. Kuroko says it is to be expected, since Tokiwadai came up second place last year in the festival's sports competitions. She asks Mikoto if she wants to go shopping and eat out later. Mikoto jokes that Kuroko has been eating out a lot lately, and she'll become fat if she doesn't stop soon. Kuroko suddenly enters her stall and tries to grope her, but Mikoto punches her out.Nonetheless, the two go shopping. While Kuroko browses an underwear store, Mikoto stands outside and sees a blimp advertising how a shuttle retrieved something from Tree Diagram's wreckage. Kuroko joins her and comments that several countries have launched shuttles to try to salvage something useful from the wreckage.Kuroko drags her roommate into the store. Mikoto becomes interested in some breast pads (she's flat-chested). Kuroko becomes shocked and asks if she's trying to improve her figure to impress a guy, and remembers the time she went on a date with Touma back in the Three Stories arc. Mikoto blushes and says they're not for him, but Kuroko gets jealous and can easily tell she's lying.
Kuroko's phone goes off. It's her Judgment colleague Kazari Uiharu, who reports that a robbery occurred in District 23, which specializes in aerospace technology. Kuroko is sad that her time with Mikoto has been cut short, but she bids her roommate farewell and leaves for Judgment's headquarters.Kuroko meets Uiharu, and finds that they are the only members of Judgment on duty at the moment. Uiharu uses her computer to show footage taken from an outdoor security camera at the scene of the crime. The footage shows a car being blocked by two others. The assailants beat up the people in the first car and run off with a suitcase. Kuroko finds it suspicious that the victims were carrying transceivers instead of cell phones. She asks what was stolen, but Uiharu says the suitcase is designed to by completely airtight and block radiation like X-Rays. Kuroko wonders if the case will be taken to outer space later, but Uiharu thinks it may be the other way around.
With the help of Uiharu's directions, Kuroko tracks the robbers to an alley. She quickly teleports in and snatches the suitcase from them, then tells them they are under arrest. They pull out guns, but she quickly knocks them out with a combination of teleport skills and martial arts. She takes note of their outdated guns and realizes they are foreigners.She sits on the suitcase to rest and gets a phone call. Mikoto asks her to come home quickly and hide her stuff before their room gets inspected by the Dorm Supervisor. She also tells her to be careful because the weather channel said it will rain soon. Kuroko asks where she is, but she hangs up. Suddenly, the suitcase vanishes, causing her to fall on her butt. Before she can get up, a corkscrew impales her in the shoulder. She grunts in pain and looks up to find a girl holding the suitcase and a flashlight. It's the same girl who brought Motoharu in and out of the Windowless Building during the Hyouka Kazakiri arc, but of course Kuroko doesn't know that. The girl says she is a teleporter like Kuroko is, but superior because she doesn't have to touch things to move them. Nonetheless, Kuroko tries to teleport some of her needles into her, but she backs up about a foot and they miss. She tries again, but the girl effortlessly reverses the action and the needles stab Kuroko instead, making her collapse in pain.The girl laughs and says Mikoto Misaka must be really desperate if she is involving her younger classmates in cleaning up her mess. Kuroko asks what she is talking about, and the girl apologizes, saying she assumed she knew. She starts talking about how Mikoto was involved in an experiment and was unable to end it until someone interfered. The suitcase contains the Remnant of Tree Diagram, its central processor, which will be needed to rebuild it and possibly restart the experiment. If she wants to know more, she should look up what happened on August 21 (this is the day Touma beat Accelerator and ended the experiment). Kuroko gets up despite her injuries and tries to attack, but the girl gets away.Meanwhile, Accelerator tries to give Last Order a bath, but the hyperactive little girl keeps horsing around and splashes soapy water in his face, making him tear up. She laughs about how he can't reflect the water because his collar is off. He begs Aiho Yomikawa for help, but she says he's on his own for this one.Kuroko staggers home, locks herself in the bathroom, strips to her underwear, and treats her injuries. She calls Uiharu and describes the girl she fought. Uiharu looks her up and finds that she is Awaki Musujime, a student from Kirigaoka Girl's Academy with the Level 4 ability Move Point. Unlike Kuroko, she doesn't have to touch things to teleport them, and she can teleport heavier objects farther than her. Her only weakness is that ever since an accident a few years ago, she dislikes teleporting herself and only does it if forced to.Mikoto comes home, and Kuroko manages to talk her out of coming into the bathroom and seeing her injuries. It works and she leaves. Kuroko thinks about August 21. All she knows about that day is letting Touma into her room, then the wind going crazy. The next morning, the railway area was found to be totally wrecked, and Judgment and Anti-Skill were called to help clean it up. Kuroko found one of the coins Mikoto likes to use for her Railgun attack in the wreckage and pocketed it, but let it slide from her mind until now. The incident has apparently not been entered into Academy City's records, but there are a lot of conflicting rumors about it.
After bandaging her injuries and getting dressed, Kuroko runs out, determined to find out what Mikoto has gotten herself involved in. As night falls, she uses a combination of Roof Hopping and teleportation to get around. She hears an explosion at the construction site and finds Mikoto fighting Awaki and her thugs. As Kuroko hides, Mikoto demands the suitcase, but Awaki says she can't stop them, and she might as well give up, the clones are as good as dead. Awaki causes several people to materialize between them and warns her that they are civilians, then escapes. Kuroko is amazed and says now its her turn, then leaves without Mikoto noticing her.Meanwhile, Misaka 10032 wakes up from her hospital bed. She strips off her hospital gown and gets dressed, muttering that she has to hurry.Awaki teleports to the fourth floor of an empty building and settles in its restaurant. She's tired and nauseous, but gloats about successfully escaping. Suddenly, needles pierce her body and a corkscrew pierces her shoulder. Kuroko appears, saying that's payback for the injuries she suffered earlier. She talks about how a few years ago, Awaki accidentally teleported herself into a wall, which was extremely painful and almost cost her her leg. Ever since, she dislikes teleporting herself and has a 3 second delay if she does. Since she cannot use her powers to their full potential, she lost the chance at becoming the #8 Level 5 esper. Kuroko mocks her.Awaki asks if it is worth fighting for someone like Mikoto who doesn't even keep her in the loop, and Kuroko says it is. Kuroko readies her needles and Awaki readies her flashlight. They fight.The two teleport all over the room, getting several hits on each other with fists and improvised weapons. Awaki even smacks Kuroko with the suitcase. Eventually, Awaki teleports several tables over Kuroko, and they fall on and pin her. She is in too much pain to concentrate enough to use her powers. Awaki mocks her and demonstrates that she can use her powers even when she is in pain as the corkscrew and needles were still inside her during the fight. She teleports them out of her, then tears her jacket into strips to bandage her wounds. While she does this, she talks about the Level 6 project without revealing any names, so Kuroko still doesn't know about Accelerator and Mikoto's clones.
Misaka 10032 finishes getting dressed and has a conversation with the other Misakas using the Network. The other clones wonder if she is well enough to do her mission, and she says she is, then exits the hospital through the window. Last Order was part of the conversation and was speaking out loud. Accelerator tells her to be quiet because he's trying to sleep. Meanwhile, in their apartment, Index decides to make up a tongue twister, but comes up with "Touma is a twat that takes tofu from the toilet". Touma is of course insulted and complains, but she gets pissed at him for mocking her "genius" and bites him. Misaka 10032 knocks on their door and asks for Touma's help to save her and her Sister's lives once again.Mikoto runs through the city, trying to find Awaki and the Remnant. She swears she will not allow the experiment to be restarted and have Accelerator kill her Sisters again. She hacks the city's security systems using a phone booth, cell phone, and her electrical powers, and finds that a fight is apparently going on in a building, and decides to go there, but runs into Touma. She asks him why he is here, and he says he's been filled in to the situation, and there's no time to waste.
Awaki says although the Level 6 experiment could potentially be restarted if Tree Diagram were rebuilt, that is not what she wants it for. She's simply curious to see if intelligent animals like dolphins and ants could be given esper powers, and such a project would require a supercomputer like Tree Diagram. She choose to work with an outside organization because she doesn't have the expertise to repair the Remnant herself. She walks up and caresses Kuroko's face, then offers that she join her. Together, they could seek the answers to several aspects to their and other esper powers.Awaki confides that when she first discovered her power, she was scared and saw herself as a monster at first, especially since she accidentally hurt some people when she was still getting the hang of it. She is sure Kuroko had similar experiences.Kuroko refuses and mocks her, saying she couldn't be any more wrong about her. When she discovered her power, she just saw them as a useful tool. Esper powers are neutral, and dependent on their user. Awaki has no one to blame for her misfortunes and crimes but herself. Using all her strength, she manages to get the tables off her. She says even though she can't use her powers, she'll still stop her, then picks up a lamppost and charges. At the last second, Awaki pulls out a gun and shoots her in the gut. Kuroko falls, and the lamppost crashes through the window.
Extremely upset by Kuroko's words, Awaki falls to her knees clutching her head and screams. Her body emits light and several objects swirl around her, randomly teleporting in and out. The effect ends and the objects fall. Awaki says Kuroko will pay for spurning her offer and aims the gun at her, but a spoon got teleported through the barrel, making it useless. She laughs and throws it away. Even in her dire situation, Kuroko still taunts her. Awaki kicks her and explains that her teleportation mass limit is 4,520 kilograms, and she's about to bring something of that mass down on her head. She leaves the room.As Kuroko lies on the floor helpless, the coin she collected from the railway area falls out of her pocket and rolls out the window, falling to the street below. The room lights up and she realizes the massive object Awaki threatened to crush her with is coming, and will most likely collapse the building with its weight. She resigns herself to her fate and regrets not being able to see Mikoto, the person she loves, again.
On the street below, Mikoto finds the coin and apparently deduces the situation immediately. She uses the coin to fire a Railgun attack through the building. Kuroko shouts at her not to come, or the teleporting object will squash her too. Suddenly, Touma appears, using the flying debris from the Railgun to run and leap all the way up to the fourth floor and grab Kuroko. He notices the large object slowly materializing above them and punches it with his right hand, causing it to disappear. He calls down to Mikoto that her roommate is safe, and Mikoto sighs in relief. Kuroko asks her rescuer who he is before passing out.Note: In the light novel, Kuroko doesn't pass out and asks Touma why he saved her. He says he would save anybody who needs it without hesitation, but if he had a personal reason, it is because he made a promise. It's the unheard promise he made to the man who impersonated Mitsuki Unabara: to protect Mikoto Misaka and the world around her. Kuroko is part of that world. Now, all that's left to do is find and destroy the Remnant.Awaki staggers through the streets with the suitcase. Since she teleported herself to get out of the building, she's exhausted and nauseous. She calls her organization and reports that she has the Remnant, but hears gunfire over her radio receiver. An Anti-Skill squad led by Aiho Yomikawa found her teammates and are rounding them up.
Frustrated, she wonders what to do now, when Accelerator appears, using a cane to walk. He says Last Order explained the situation to him and begged him to help, so he's here to destroy the Remnant. Awaki is absolutely terrified, muttering that she doesn't stand a chance against the #1 Level 5. However, she starts to laugh when she remembers the reports that he was shot in the head and suffered brain damage. She is now confident she can beat him since he's not as powerful as he was before.Accelerator mocks that line of thinking by pointing out that just because he's gotten weaker doesn't mean she's stronger than him. He drops his cane and activates his collar, then stomps the ground, creating a massive crater and shockwave. She teleports into the air to avoid it, but the shockwave shatters several windows, so she teleports higher to avoid the falling glass. While in midair, she reaches her limit and throws up.
He leaps up and uses his wind control to move himself next to Awaki, then throws a punch. She blocks it with the suitcase, but to her horror, the punch shatters the suitcase and the Remnant into a million pieces. He says it's over and punches her in the face, rocketing her into a fire escape in the distance, unconscious and with blood streaming from her nose.Accelerator turns off his collar, retrieves his cane, and walks away. He muses that due to his weakened condition, he may have to give up his title of #1 esper. Oh well, whenever he's in front of Last Order, he'll always be the strongest.The next day, Touma and Index go to the hospital for a visit. Index asks what happened last night, but he shrugs and says it's not important. Apparently, Touma found Awaki and called an ambulance for her. He and Mikoto have no idea what happened to her and why the Remnant was destroyed.Last Order thanks Accelerator for what he did and talks about Yomikawa's part in stopping Awaki's associates, but he just wants to go back to sleep. In the light novel version, she gets mad at him for not paying attention to her and cuts off his collar's connection to the Sister's Network, rendering him unable to speak.Touma entered Misaka 10032's hospital room with flowers, but found her naked in a pod, as she was undergoing the adjustments to fix her lifespan. He then entered Kuroko's hospital room with flowers, but found her in her underwear and Mikoto helping her get dressed. In the light novel, Mikoto angrily slapped him across the face, but in the anime, Kuroko slaps him. He leaves.Kuroko looks out the window and is glad that the weather channel was wrong about it raining soon, as it's a beautiful day. She says she's finally caught a glimpse of the type of struggles Mikoto goes through. Mikoto looks as though she's about to finally tell her about the Level 6 experiment, but Kuroko cuts her off and blames herself for getting hurt. For now, she will recover and then train hard to catch up and be able to truly fight by Mikoto's side.