Toaru Kagaku no Railgun: Arts and Sciences City SS is a short story in Arts and Sciences City that takes place in the time period between September 3rd to 10th. Academy City have a exchange program with the rest of the world that allows some students to travel for this week to other places, and some students are allowed into Academy City during this time.
Mikoto, Kuroko, Saten and Uiharu went to the Arts and Sciences City, made on a artificial island off the coast of California for a field trip. The Arts and Sciences City is known as a city that has cutting edge technology (in terms of the standards of the 'Outside' of Academy City - ie it is still far behind that of Academy City's), and is trying to take over Hollywood as the entertainment capital of the world. Stuntsmen and shows occur frequently at this city, and anything out of the ordinary is treated as another show. Due to the climate apart from sleeping everyone wears their swimsuits all the time.
As Mikoto, Kuroko, Saten and Uiharu went to the beach for some relaxation, they talk about their swimsuits. When Kuroko appeared with her skin-coloured swimsuit that covers only the bare necessities the rest of them watch on dumbfounded. Even the bystanders are put off by Kuroko's appearance as her generous show of skin is more of a horror show than a fanservice.
Soon afterwards they meet Beverly Seethrough and they talk a bit about how the Arts and Sciences City was established, and the rivarly with Academy City. Only after Beverly left did they realise she's a famous director, and Mikoto is agonizing that she forgot to get a autograph (though the four of them were too busy lamenting the difference in bust size between them to care about that earlier).
Then Mikoto and others was dragged into a mock-fight between actors dressed as pirates, and Mikoto is annoyed that they were involved without choosing to. Then they saw two strange planes being chased by modified F-22 planes. The planes being chased are oval shaped and look like a flying fish, 5m in length with four wings, and made of wood, cloth and obsidian stones. It looked like two canoes being stuck together. As everyone wonders if this is another show, Mikoto found it strange that something made of wood can travel at Mach 1 without falling apart.
Those planes are called 'Mixcoatl', meaning 'snakes of the sea of clouds'.
As one of the Mixcoatls was shot down and is about to crash onto civilians on the beach Mikoto stepped in to blocking the crash landing using the iron sands on the beach. Most people treated it as another show. As the crashed Mixcoatl struggled to get back up tourists approached it without caution, still thinking it's just another attraction. Mikoto tried to blast it back into the ocean after seeing it fired off a missile onto the tourists and moved to grab a arcade coin hidden in a secret compartment in her sandals, but it got jammed due to the sand. Mikoto blasted the missile down but the Mixcoatl then crawled over to her and tried to take her down, somehow able to walk on land like a insect. As Mikoto is pinned down by the Mixcoatl she saw the cockpit is empty and though she can't read the glyphs from how it is constantly changing and looks like decreasing she deduced it is set to self-destruct on her. Mikoto then brought the iron sands around her to form a barricade to prevent bystanders to be caught in the blast, and blasted the Mixcoatl away using it as a bullet for her railgun. The crisis is averted for the time being.
Beverly looked on and only sighed that CGs, VFXs and the such cannot match a real esper. Which proved her point back when talking to Mikoto and others that Arts and Sciences City currently only exists because Academy City has no interest in the entertainment sector.
Afterwards Saten and Uiharu tried to look for a place for dinner, and Mikoto rushed to them with tears in her eyes and a scared expression on her face. As Saten and Uiharu asked why Mikoto passed a catalogue to them, showing more swimsuits that puts what Kuroko had on earlier to shame. Kuroko was muttering to herself what should she wear next while looking at that catalogue, and Mikoto ran out from her shock. Both Saten and Uiharu regretted looking through that catalogue, seeing swimsuits that only has 5cm of cloth to cover down there, and instead of being 'T' shaped it's somehow 'I' shaped and none of them can think of just how it can stay on. After seeing someone else walking by with a sarong Mikoto decided to go forcibly wrap up Kuroko with that, then the four of them went out for dinner.
Mikoto and other met Beverly at dinner and they talked more about the Arts and Sciences City, with Saten commented once to Uiharu she suspects Beverly is at least 'G' cup, and possibly maybe even 'I' cup. Beverly commented offhand she is 'L' cup, much to the horror of the four developing girls (Beverly's bust size is possibly larger than all of their's combined). Mikoto commented even sunscreen can be used as weapons as she approached Beverly with a black aura, and after a few minutes Beverly left they realised once again they forgot to get her autograph.
After getting back from dinner, Mikoto decided to hack into the Arts and Sciences City's network to find out more about the incident with the flying fish, in case something else similar will happen. Mikoto got in and found the defenses is ridiculously easy to break through since she's used to better defences in Academy City. She found a sub-network that's not connected to the main network and decided to go check that place out personally.
Mikoto found herself at a building site 3km in diameter, named 'Large Launcher'. Here is a place to launch rockets in the film that led to this city's creation, and it was mostly left as is due to fans obessessions of wanting to keep it that way. As Mikoto picked the electronic lock and is about to go in she's found by Saten, who mistakes Mikoto as trying to get into a Casino and gamble at a legal place to do so. As Saten rushed in Mikoto tried to follow her and tell her it's not a Casino, but after Saten is convinced the electronic lock is back online and messing with it once more may lead to alarms sounding, so Mikoto had to take Saten with her to go in deeper.
After a while they found a hangar filled with remnants of the Mixcoatls retrieved from battlefields by the Arts and Sciences City. As Mikoto tried to take a photo of the name 'Mixcoatl' on the side of a plane to figure out what it is later, Olive Holiday came in and told them what it meant. Mikoto and Olive doesn't not get along well and is on the brink of open war before Olive recieved a call from the Adminstrators (Equivalent to Academy City's Board of Directors, except there is only 5 of them for the Arts and Sciences City) telling Olive to stand down. If a Level 5 of Academy City were to go missing on a field trip Academy City will see this as a provocation and possible leak of valuable DNA maps, leading to an all out assualt on Arts and Sciences City that will include but not limited to economics, military and information warfare. Olive grudging acknowledged there's more to be lost than gained by opening hostilities and told some of her underlings to escort both Mikoto and Saten outside. If given the chance Olive will be more than willing to kill Mikoto.
The next day, Mikoto and others are going back onto the beach. Mikoto went through Kuroko's luggage and managed to find a seemingly normal swimwear and forced Kuroko to wear that. Much to their surprise that 'normal-looking' swimwear looks really wrong on Kuroko for some reason, hurting their eyes almost as bad as her revealing ones. Kuroko had enough that either way there will be trouble so she activated her secret weapon - markings started to appear on her swimsuit and for some reason though not much skin is showing Mikoto, Saten and Uiharu all feel really awkward just looking at Kuroko.
Kuroko revealed this swimsuit is a paradigm of Academty City technology, based on the behaviour of 38,000 different kinds of animals during mating season and make markings specifically to attract other people. Within the suit are possible small sound speakers and aroma patches that aids the effectiveness of attraction. Kuroko stated she didn't want to use this secret weapon if she could help it, but since Mikoto forced it onto her she had no choice. Mikoto asked her to turn off that military-grade weapon already and go put on one of those revealing ones if she must, but Kuroko declined, forcing Mikoto to shock her. After that Mikoto tried frantically to find the off-switch with a blushing face as Kuroko didn't say how to stop it before she fell unconscious, and eventually turned it off.
Later, Saten went looking around for a coconut drink, but was ambushed by Xochitl wearing traditional Aztec clothing. She had to give her Mixcoatl to another comrade that was stranded so she had to stay behind to scout out this city. Xochitl warned Saten to not do anything unless she wants to be cut up by the obsidian knife she has, then told Saten to go buy a swimsuit for her so she can fit in. When Saten asked what's stopping her to just run away Xochitl shoved some sort of powder up Saten's nose, and told her she can make that explode remotely if Saten doesn't help her.
Saten met up with Beverly while shopping, and gave the excuse that one of her friends had a waldrobe malfunction and had to hide in the bushes for the time being. They then had fun trying to find a swimsuit to payback the 'obnoxious friend' of hers. Saten went back to Xochitl and asked to have the powder taken off her, and Xochitl obliged while trying to wear her swimsuit. She then found out Saten bought her a H-swimsuit made only of glass beads and strings, and any violent movements will likely result in it breaking. This swimsuit can't even get wet otherwise it might just dissolve. Xochitl then asked Saten to accompany her, otherwise they will both have to end up naked since Xochitl has the resolve of taking down Saten with her in her embarassment.
Xochitl seems to wander around meaninglessly in the city with Saten following her, looking at the city's defences. Xochitl talked a lot of jargon of attacking and defending a city, all of which went right over Saten's understanding.
Then a barrage of missiles was bombarded by above onto the city in general, and one of the Mixcoatls flew down using the resulting panic as cover to retrieve Xochitl. Tochtli came to pick Xochitl up and they went over the findings in the Aztec language, so Saten understood none of it. Tochtli mentioned the 'Cihuacoail' (Snake of the Sun) will be used in their attack on the Arts and Sciences City, and that Xochitl have bought a fine souvenir for their male comrades (her H-swimsuit). Xochitl threatened to mug Tochtli for her clothes and leave her in that H-swimsuit if she doesn't help her find a alternative as the two of them left Saten on the ground.
Later Mikoto, Kuroko and Uiharu went to a buffet, but Saten said she was tired and went back to the hotel early. Saten is worried about Xochitl and the flying fish attacks earlier, and thought about asking Mikoto for her thoughts but Mikoto isn't back yet. Saten the decided to go out looking to get to the bottom of this, completely forgetting that last night when she did this she almost died. As Mikoto and other came back they just missed Saten running out.
Saten went back to the hangar with the remnant of the Mixcoatls through a hole in the fence, and found something else in a room next to it filled with red light. As Saten tried to leave from the horror within that room she was caught by Olive.
Next day, Kuroko tried to get Mikoto to a nudist pool and Mikoto threatened to fry her. Then Uiharu came to ask them have they seen Saten, and they figured out Saten has gone missing. They got one of the students that came with them using her ability 'Psychometry' to try and figure out where Saten has gone. That student found Saten went out to try and find the hidden secrets of Arts and Sciences City, and said that's a bit much for students on a school trip.
Olive and her underlings talked about their past jobs, and they see themselves as the 'World Police' that tries to keep war from breaking out. They then got the orders from above to eliminate Saten and make it look like an accident.
Mikoto tried to hack the network again to find where has Saten gone, but ended up running into a firewall. It's not difficult to break through, but it will take time they don't have. Uiharu took the data from Mikoto and hacked through it in minutes, breaking down the defences faster than her opponent can repair it.
Olive and her underlings are trying to make Saten appear like she fell into the sea from a cliff, having ignored the danger signs. As Saten is on the verge of drowning se asked why is Olive doing this, and Olive replied it's to start up a rival esper development organisation against Academy City. Even with the ships rebuilt it cannot fly, and they deduced it runs on laws unlike normal ones. If they try to steal secrets from Academy City they will be hunted down, so they went and tried to start esper development from another source.
Mikoto and others tried to get to Saten, but was caught in one of the air strikes from the Mixcoatls in their attempt to cripple the Arts and Sciences City of their transporting system and isolte from mainland America. The train station they're next to is disabled since the tracks are destroyed. Beverly at the station told them they can't move on, and they all decided to go back to the hotel instead to get Kuroko to teleport them to where Saten is.
Saten thought Olive had it wrong - those ships aren't esper abilities, and it is apparant even to a Level 0 though Saten cannot say just how different it is from the Academy City techniques. Olive does not know that as she has no expertise with esper development. As Saten tried to say that she went under the surface and is about to suffocate.
Xochitl ends up saving Saten as she attacked Olive and others, then yelled at Saten for getting involved in something she shouldn't have if she was going to be eliminated like that. Xochitl told Saten 87% of the Arts and Sciences City will be erased in one blast from their 'Cihuacoail', and told her to get off the island. As Xochitl and Tochtli flew off they can see Saten waving at the two of them while they continued their bombardment of the city.
The city is still in a uproar from Mixcoatls' bombardment, but both Kuroko and Mikoto found it strange that the damage wasn't more severe. The enemy didn't strike as soon as the transport system is crippled so something is wrong. Saten woke up soon after, having collapsed from exhaustion earlier. Saten told Mikoto and others about Xochitl and the Mixcoatls, and then was banged on the head by all three of them consecutively. What Saten did was like playing Russian Roulette, firing five shots at herself and didn't get the bullet - a miracle. Xochitl told Saten to escape on one of the 12 emergency lifeboats that can hold all of the city's population when necessary.
Mikoto thinks that she belongs on neither side, so they can work in a manner to reduce any casualties to smallest possible. As they planned on what to do next their hotel's electricity is cut, though from their window they can see lights are still on everywhere else. A black-ops force came to attack them after discovering Uiharu's hacking (even if her skills is beyond anything else, staying in enemy territory in a prolonged period of time will still expose her), blowing one of the walls through to enter instead of coming through the windows. Mikoto used her powers to build a wall to stop bullets and then used lightning to defeat the intruders. It turned out it's Olive and her team.
Olive says what they need to do isn't to just keep the peace but to make sure 10, or even 100 years down the line the world won't step onto the path of ruin. If Academy City technology become widespread there will be more Level 5 espers and that will result in war unimaginable. Mikoto calls her logic a complete farce, and the world doesn't operate by being commanded by people like her - it's decided by everyone themselves. Olive isn't convinced by Mikoto's preaching (she's no Touma, and Olive isn't exactly someone that can be reasoned with), and says the situations has changed. Mikoto stepped out to continue to think on what to do next.
Meanwhile, the Adminstrators of the Arts and Sciences City had their request of intervention from the American military denied. They are also ordered to freeze all plans and destroy all information they possess. It's not that the Mixcoatls are opponents beyond the American's power to defeat, but someone else more politically influential than these Adminstrators interfered. Then their communications are hacked by the General Superintendant Aleister of Academy City who basically asked if they need Academy City's help. One of the Adminstrators asked are the Mixcoatls part of Academy City's forces and is he behind all this, to which Aleister replies he is not. Aleister told them they have violated a agreement between the two worlds (Science and Magic, but it's not said outright here), and asked them one thing:
If the Arts and Sciences City was turned to ash and sinks into the ocean, are they still going to use the 'it's a show' excuse?
At District 23 of Academy City an HSB-02 supersonic bomber is being prepared with a AIM tracker machine. If worst come to the worst this unit will be sent out to retrieve Mikoto and destroy everyone else.
In the end it turned out the Arts and Sciences City has obtained a crash-landed aircraft from the Aztec magicians, and plans on reverse-engineering it to gain access to its powers and set up a rival organisation against Academy City. The Aztecs seeks to retrieve their aircraft and launched an invasion using flying fortresses and a air force of their own, disregarding normal civilians' lives. Xochitl decided to go against their Tecpatl's (the leader for this operation) orders, and helps citizens evacuate instead of killing them all to prevent knowledge leaking out. This results in her punishment and lead to her conflict with Etzali in Index Vol15.
Mikoto went head to head with the full might of the Aztec airforce using her electricity powers to strip hydrogen from water and using it as propulsion. She uses those hydrogen wings to fly, but this has nothing to do with 'awakening' such as that of Kakine Teitoku's or Accelerator's. Kuroko helps Mikoto fight by holding onto Miko as she flies and teleports the two of them to evade attacks Mikoto's wings cannot dodge. Xochitl saw Mikoto's powers and is stunned by her prowress, as to her defeating an entire army almost single-handedly is supposed to be unheard of in the events of the Magic Side. How much Xochitl knows of people such as 'Saints' is debatable.
The novel concludes with Arts and Sciences City being disbanded.
- This show that Mikoto can use water create wing to fly but without navigation.