With the strong teamwork of ITEM's AIM Stalker and Meltdowner, Mikoto becomes corners. However, Mugino soon recognizes that the one they are fighting is none other than the third-ranked esper of Academy City, the Railgun, and the decided to mow her down in single battle.
Unable to answer her enemy with her own abilities to its full potential after tiring herself, Mikoto tries to fight using the stuffed bombs that Frenda left. However, Mugino also shows her how dark organizations such as theirs fight, by using her "trump card" to cover her weaknesses, she tries to strike Mikoto down. Mikoto however, still succeeds in the destruction of the facility after somehow going through the eye of a needle.
And yet, Mugino continues her unrelenting pursuit.
Amidst the wreckage of the S-Processor Laboratory, Misaka Mikoto finds out that the attacks have stopped. However, she remains vigilant, knowing that her attackers wouldn't let her off the hook that easily. As she weighs her next possible moves, she discovers a strip of explosive tape, the one Frenda had used on her earlier. Upon following that strip, no only did she find the entire facility lined with the tape, but also the stuffed toys that are placed in strategic areas.
As Mikoto stares upon the button-eyes of a doll she had picked up, she decides to use them as weapons of her own.
Meanwhile, Frenda and Takitsubo Rikou decide to retreat from the facility and speeds away in an armored van. As Frenda decides to relax after a tense fight with a Level 5, Rikou takes this chance to recover after the usage of her ability has left her completely fatigued. However, Frenda discovers that she just forgot one important thing to do, and it was to dispose of her bombs.
It was too late for Frenda. As Mugino waits for Mikoto to show up at a large well-lit room inside the facility, she discovers that Mikoto has picked up Frenda's dolls, and is using it as her weapons, using electricity to detonate them and magnetism to manipulate their movements in mid-air. Although fending off the dolls are an easy task for Mugino, doing so while protecting the database nearby is something troublesome for her. On the other hand, Mikoto uses the moment of advantage to overwhelm Mugino through sheer numbers.
However, Mikoto is thrown into a corner as Frenda's dolls are destroyed by Mugino's Meltdowner beams, spread into several dozen beams using silicon cards. Mikoto watches in shock as Mugino, introducing herself as the fourth-ranked Level 5, destroys Frenda's dolls in an instant.
Mikoto is forced to retreat her last remaining doll as Mugino continues to gloat over her imminent victory. Then, she sprints towards Mugino and uses the doll as a diversion. Mugino is then taken aback when another doll flies towards her. However, Mugino was able to swat it away, using her ability to interfere with Mikoto's electricity.
Then, as Mugino prepares for her killing strike on Mikoto, the doll she swatted earlier, which is much heavier than expected, crashes straight into Mugino's temple, knocking her out instantly.
With Mikoto stealing victory from Mugino, she heads to the database room of the facility and used her last doll and her electricity to destroy everything inside. However, unlike in her previous attacks, she decides to leave early to avoid from getting caught in the fires herself.
As she returns to the room where Mugino was lying cold on the ground, Mikoto is surprised to find a small puddle of blood on the ground instead. Mugino appears shortly, delivering a barrage of Meltdowner beams before kicking Mikoto on the gut. At that moment, the bloodied Mugino is in rage, firing her beams where Mikoto stands, determined to finish her off for managing to injure her. Meanwhile, Mikoto remains on a defensive, focusing more on a clean getaway instead of a direct confrontation with Mugino.
Mikoto leaves the room and heads back to the many hallways that line the facility, planning an escape using a particular route she discovered earlier. This is not easy, though, as Mugino continues to fire beams at the fleeing Mikoto. Soon, Mugino's assault is interrupted by a call from Saiai, reporting the smooth completion of her mission on her part. Their conversation is rather short due to Mugino being too focused on taking care of Mikoto, so Saiai just relayed a message for Frenda instead: that "she will get a spanking" when everything is over.
Mugino and Mikoto soon reach a part of the facility filled with pipes and metal tubing. Mikoto uses the metal pipes to slide away from Mugino, but the Meltdowner quickly paves a path for herself, destroying Mikoto's footing and causing her to plummet to a nearby platform while Mugino reaches her with ease. Mikoto, despite the effects of fatigue setting in, still shows barely enough power to defend herself from Mugino's beams. However, with Mugino dangerously close to her, one wrong step would be her demise.
Mikoto laughs as Mugino urges her to use her most powerful ability against her, telling her that she no longer has the stamina to use her ability extensively, let alone fire a Railgun. However, she points out that the platform they are standing on is lined with Frenda's explosive tape, a part of her plan to close off any escape routes. Mikoto then uses a small spark to denonate the tape, and in an instant, both of them plummet to the ground, except for Mikoto, who used her magnetism to cling to a nearby metal section. Mugino manages to survive the fall using the recoil of her Meltdowner beams, but she still injured her right leg in the fall.
As Mikoto rests, she realizes that she still needs to take care of another facility, but is too weak to make a decent spark. Meanwhile, Mugino desperately searches for information about the project. After beating up a random researcher fleeing from the S-Processor Facility, Mugino reads on about the Level 6 Shift Project. At first, she is amused at how Rank One ends up killing 20,000 clones to reach Level 6, but Mugino becomes interested as she realizes that Mikoto is being dragged into the darkness of Academy City, slowly but surely.
Mikoto manages to return to her hotel room, battered, bruised and overly fatigued. However, the sleep allowed her to recover some of her strength. After finding her clothes tattered by the fights the night before, she quickly changes back to the Tokiwadai Middle School uniform and decides to so some surveillance on the S-Processor Neuropathology Analysis Laboratory.
Upon closer inspection, Mikoto discovers that most electrical devices have been shut down and security is obviously lower than expected. Despite suspecting that it may be a trap, she heads inside. There, she discovers that the facility has been completely shut down, and all data files have been erased. Upon reading news of the facility filing bankruptcy was the moment Mikoto wonders if the last research lab had given up after losing its sister facility.
The feeling that everything is over seems surreal to Mikoto. As memories of the clone she met for the first and last time... of her death... of Accelerator... and the Sisters flashed in her head, Mikoto realizes that everything that had happened will not disappear, and the only left to do it to move forward. However, what's important to Mikoto right now is that the experiment is over, and that the remaining Sisters no longer need to die.
With that, Mikoto decides to return to the friends that she had left behind all this time.
As Mikoto visits a certain vending machine, she sees a certain unfortunate boy lose his money as it was eaten by the vending machine. At that moment, all Mikoto felt is relief.
- The first actual single battle between Level 5s occur between Misaka Mikoto and Mugino Shizuri. Misaka Mikoto defeats Mugino Shizuri.
- Misaka Mikoto successfully cripples the second to last laboratory connected to the Level 6 Shift experiments, and later discovers that the experiment can no longer be sustained.
- Misaka Mikoto
- Mugino Shizuri
- Frenda Seivelun
- Takitsubo Rikou
- Kinuhata Saiai
- Misaka 9982 (flashback)
- Accelerator (flashback)
- Sisters (flashback)
- Saten Ruiko (flashback)
- Uiharu Kazari (flashback)
- Shirai Kuroko (flashback)
- Kamijou Touma
- Academy City Board of Directors (referenced by Mugino)
No notable characters were introduced during this episode.
- Academy City
- S-Processor Laboratories
- Misawa Cram School (flashback)
- Endymion (flashback)
- Vending Machine 7116
- Electromaster - Misaka Mikoto, Level 5.
- Meltdowner - Mugino Shizuri, Level 5.
- Accelerator (ability) - Accelerator, Level 5.
- Meltdowner + Silicon Burn (this allowed Mugino to greatly enhance the power of her Meltdowner attack by splitting it into many different green beams of light, causing a greater range of destruction)
- This episode marks the first time two Level 5s do battle in single combat in an anime adapatation. This is unlike Mikoto and Accelerator's confrontation, where the latter didn't even get the opportunity to fight former.
- Touma does the preview narration for the next episode, the first time he does so in Toaru Kagaku no Railgun.
- The hotel that Mikoto used as a her "coin locker" that appeared in episode 3 returns.
- Touma getting a beverage from the vending machine is a reference to his appearance in the same machine back in episode 10 of the first season of Toaru Majutsu no Index, indicating that the timeline for Index's version of the Sisters Arc has begun.
No notable references to culture were introduced during this episode.
- Scenes from episode 5, 6, and 7 are reused as flashbacks in the episode.
- An animation error occurs when Mikoto tries to dodge Mugino's Meltdowner beams after finding out that she is somehow still conscious. Mikoto's head is cut-off, indicating that the frames were not aligned properly.
- The animation used for Touma giving his money to the vending machine is exactly the same one from the 10th episode of Toaru Majutsu no Index.
- How was Mikoto not able to see Mugino before she can sneak up on her after she returned that Mugino has gone missing in a large open area?
- Why was ITEM hired in the first place?
- Where will the clones go now if the experiment can no longer be sustained?
- What did Mugino mean when she said "Just what the hell are the board of directors thinking?" Are they involved somehow?
- Frenda: "Hopefully you can find another place sometime." —to Rikou after she tells that ITEM is the only place for her.
- Mugino: "Do you really think you can overwhelm me with numbers? Silicon Burn. Don't they teach you to make up for your weaknesses in Combat 101? Don't underestimate ITEM, you brat!" —to Mikoto after she unleashed a hail of doll bombs on Mugino.
- Saiai:' "I'm giving you a spanking." —Mugino's message to Frenda delivered by Saiai.
- Mugino: "Parry, parry, parry? You're killin' me, kid! Do you really think your childish quarrels could erase the darkness of this city?!" —said to Mikoto.
- Mugino: "Would you rather turn into some fatty lump of meat, or would you rather bet on your chances of imprisonment and live trying to escape your fate? Which will it be?" —said to a S-Processor researcher.
- Mugino: "Sink into the depths of the darkness, kicking and screaming. Into the depths of the abyss beneath Academy City. Won't you?" —said regarding Mikoto's fate.
- Mikoto: "Everything that's happened up until now won't just disappear. There's a lot that needs to be done to move forward. But... The experiment's over! Those girls... Those girls don't need to die anymore."
- Mikoto: "Girls... I'm coming home."