In a certain part of Academy City, in the middle of the night, a certain white haired boy known as Accelerator is filling his shopping cart with an unusually excessive amount of black coffee cans. After, getting outside of the store, he is met by a group of delinquents who tries to attack him, though obviously to no avail, as they're attacks are immediately redirected by his power. He mentions to himself that since his defeat in the hands of Kamijou, he is no longer considered the strongest in Academy City, even though his powers still remain and that he is still a Level 5. As a consequence, delinquents have increased their attacks on him no matter how many times he puts them down. While leaving, he asks himself what exactly changed within himself.
While walking, he passes by a certain apartment complex, and is annoyed by the noise created by two certain characters. He uses his vector powers to mute out any sound from him as he continues to walk alone. However, unbeknowngst to him, he is being followed by someone. After a while, the person comes close enough to him for him to notice, and uses his vector powers to unmute sound. With this, Accelerator discovers that it is from a voice of a little girl, who calls herself Misaka, twice. Annoyed by her, Accelerator continues to walk along, ignoring the girl, though she continues to try and talk to him, telling him that she has been trying for him to notice her all this time. Suddenly, Accelerator remembers the name Misaka (much to the girl's delight), and demands the girl to remove her vestments and show her face to him. The girl naturally protests at this, however, Accelerator removes the cloth from the girl himself, and sees that the girl is completely naked, making her cry.
The girl says that she is the 2001st clone to be produced for the Radio Noise project, and says that her codename is Last Order. She continues by saying that since the experiment has been nullified, she was apparently released from her tank in the middle of the incubation process, as is the reason why she appears so small in comparison to the other clones. However, Accelerator only somewhat feigns interest in her plight. Last Order states that since Accelerator has connections with the researchers, she could use him to contact them for her. Acceleretor gives an immediate response to her that he is not interested, which somewhat disappoints Last Order since she has nowhere else to go to now.
Apparently feeling sorry for her, Accelerator lets Last Order follow him to his apartment building and pulls a couple of tricks to the very eager Last Order, much to her annoyance. When they get to his room, they discover that Accelerator's room has been trashed. Still uncaring and yet somewhat expecting of this, Accelerator lays down his purchases and proceeds to sleep on a relatively intact couch to rest. Worried, Last Order asks Accelerator if he should contact Anti-Skill or Judgment. However, Accelerator ignores her suggestions and asks what she should do since it is probably safer to rest outside than inside his room. Last Order however, insists that she stay in his room because she eanerstly does not be alone. Hearing this, Accelerator says that she could whatever she wants. With that, Last Order happy goes to lie on Accelerator's suprisingly intact bed, and warns him not to touch her in the middle of the night, much to Accelerator's annoyance as he tells her to go to sleep already.
Morning shines through the curtains of Accelerator's room, as he awakens from his slumber. Here, he discovers that Last Order is still in his room, and is hungry asking Accelerator to cook some food. Accelerator ignores her and tries to go outside, which makes Last Order grow concerned. Accelerator states that he is not someone who cooks which disappoints Last Order.
Accelerator and Last Order go to a family restaurant for their breakfast. While waiting around, Last Order inquires Accelerator regarding his hair color, being white and all. Accelerator explains that the body naturally produces pigments that protect it from ultraviolet radiation, however, since he has his auto-reflect always on, his body does no longer has the need to produce any. While Last Order happily asks herself what meal to get, Accelerator notices a person in white outside in the restaurant parking lot. It is Amai Ao, according Accelerator who is wondering what he is doing. Amai Ao who also notices Accelerator's gaze, and quickly gets into his car to try and vacate the premises. Meanwhile, Last Order notices Accelerator's agitation, which annoys him, since Last Order has apparently forgotten her main priority.
While she babbles, Amai Ao drives away in a haste, greatly concerning the Accelerator.
Finally, their order arrives to which Last Order greatly enjoys. While eating Accelerator reminds Last Order of what he did to the clones. Hearing their conversation turning serious, Last Order stops eating and responds to Accelerator. Last Order states that since she is connected to all the clones, she of course knows. Last Order states that was taught the value of being a clone, even if a single clone dies there's no way the entire Misaka network would disappear. However, Last Order says that since every single Sister's life has it's own worth, then someone will cry if a Sister were to die, and that is the reason why there would be not a single Sister have her life taken away again.
Accelerator grunts after hearing this, however, Last Order continues to explain. Last Order says that without Accelerator the experiment would never have been proposed and that souls would have never have been injected into the lifeless Misaka clone, and thanks Accelerator for it. Thinking that Last Order is joking, Accelerator smirks and reminds her that he enjoyed killing the clones. However, Last Order counters by saying that Accelerator is lying, and says that Accelerator didn't want to do the experiment in the first place. Accelerator gets mad at her observation and says that the fact that he kept continuing with the experiment means that he thought nothing of the clones' lives. Last Order once again counters him and states that Accelerator tried to communicate with the clones many times, and cites that Accelerator talking to the clones were strange, as if he wanted to establish a link with them. Accelerator demands to know what made Last Order say that his insults was meant to establish a link with them. However, Last Order refutes his statement and says that indeed all the words he said to the clones were unreserved and were insults, and actually diverges from wanting to establish with others. However, Last Order states that if one assumes that those words were used in order to get a negative response and the fact that all the insults were stated before an experiment began, then one can conclude that the words were used in order to scare the clones. Scared enough as so the clones will not want to fight anymore. Last Order says that the clones were unable to notice Accelerator's signs, however she continues by saying that: "what if a clone said she didn't want to fight anymore, what would Accelerator do?"
Having enough of Last Order's outrageous physchoanalysis of his person, Accelerator stands up to leave. However, after turning his back, he discovers that Last Order has been overcome with something. Last Order states that she in a condition where her body is incomplete, as such her current condition. Accelerator tries to get a response from a now ill Last Order, however, in a daze, Last Order asks if Accelerator is going away because there is still food left on the table. Accelerator responds that he no longer feels like eating anymore, he later takes the bill for their food and leaves a sleeping Last Order in the restaurant.
Accelerator walks in familar places for a while and arrives at a research institute. In a dimly lit and messy room with several computers running, sits a woman. She hears the door open, it is Accelerator. She is apparently familiar with him and greets him upon entering the room. She reminds Accelerator that he didn't need to break the down the entrance as his ID card is till valid. Accelerator later asks Yoshikawa Kikyou (the woman's name), where the experimental body adjustment manual for the Sisters is. Accelerator invites himself to find the manual himself and states that it should be payment for his participation in the experiment since it was cancelled.
However, Kikyou suddenly asks Accelerator an unusual question: "How did you find out?" She continues by saying that she had only notices the "problem" a few hours ago, and is still trying to debug "their" personality files. This confuses Accelerator, however, Kikyou continues to speak. She states that the "problem" is more accurate if one calls it a virus.
Now knowing what Kikyou is yammering on about, Accelerator asks. Kikyou explains, saying of special experimental instance known as the Last Order. Hearing Kikyou say Last Order being special, piques Accelerator's interest. Kikyou seeing that Accelerator already knows of "her" existence, continues to explain. She states that Last Order was never made to be a part of the experiment to begin with. The point of the Sisters was to be killed by Accelerator, and that it requires having 20,000 battles for the experiment to finish. Hearing this, Accelerator remembers the words of Last Order: she is the 20,001st. Kikyou continues that Last Order is not part of the experiment, but is the command center of the Misaka Network, and is the reason why her development has been held up, and took care of her even after the experimented was terminated. Kikyou however states that seven days ago someone has overwrote her program with malicious code, because of the effect of the malicious code, Last Order ran away from their laboratory as a response. Kikyou continues by saying that the virus will activate tonight on September the 1st on 12 midnight, which would infect all throughout the Misaka network and will go out-of-control, where they'll initiate an indiscriminate attack against all humans.
Hearing this Accelerator only laughs at the interesting situation and asks who the suspect is. Kikyou states that the most likely culprit is Amai Ao, which surprises Accelerator after remembering Ao strange behavior in the restaurant parking lot. Amai Ao, a former researcher of the Radio Noise project who is the most familiar with the clones personality than anyone. Accelerator notifies Kikyou that he just saw him awhile ago, and asks Kikyou how to stop the malicious code in Last Order's brain. Kikyou states that she is trying to investigate how to stop it at this moment, and states however, if they don't find a resolution by the time limit, then (to which Accelerator realized as well) they need to dispose Last Order.
Kikyou states that she is doing her best to prevent them from taking that option and says that Accelerator can do something as well. Hearing Kikyou's suggestion, Accelerator sarcastically remarks on how he is the person who butchered 10,000 Sister clones, and derides her for asking a villain like him to save Last Order. Kikyou responds to him by sayin that she and the researchers were the ones who made him do that, and that if there was a way of evolving Accelerator to a Level 6 without the need for killing the Sisters, then he wouldn't have to kill anyone. Accelerator just smirks at her remarks and asks her if she wants him to trust and obey her for that single reason alone. Kikyou says that she won't force Accelerator to do it, and tells Accelerator that there are two things he can choose to do now: capture Amai Ao and force him to talk about the virus' structure and resolve the incident, or secure Last Order who bears the virus in her ming and put her back into the incubation tank.
Kikyou gives Accelerator a more physical example, showing Accelerator a choice between a file regarding Amai Ao or a device that contains Last Order's personality files from a week before her infection. Kikyou acknowledges that Accelerator is more adept at destruction than protection. Accelerator agrees with Kikyou's assessment, and states that it is obvious to anyone which is the right one to pick.
Accelerator steps closer and slowly reaches towards his choice.
The scene cuts to Accelerator running in the streets of Academy City, grasping in his hands Last Order personality files, having chosen to answer the obvious choice in the end. The choice of saving her.
- Accelerator meets Last Order and discovers a virus implented into her, and decides to save her.
By order of appearance
- Redirection - Accelerator, Level 5
- Unnamed beam like projection - Random delinquent attacking Accelerator
- Accelerator Residence
- Julian Restaurant
- This marks the first time Accelerator is featured as the protagonist.
- The convenience store were Accelerator buys his coffee is the same conveniece store Accelerator goes to back in episode 10.
- Several members of the group of delinquents that attacks Accelerator appear in the first episode chasing Touma.
- The scene where Accelerator passes through Touma's restaurant is the scene from the previous episode where Touma awakens Index and accidentally insults her.
- Several backgrounds featured in the episode have all been use previously, most notably the parking lot of Touma's apartment building as well as the bridge where a view of Misawa Cram School can be seen.
- Flashbacks from the Sisters Arc are featured during this episode.
- No notable cultural references were featured during this episode.
- Only Amai Ao's yellow car is traditionally rendered.
- Why was Amai Ao nervous after noticing Accelerator?
- Did Amai Ao really input the virus into Last Order?
- Accelerator: "Since my battle with that Kamijou guy, it appears I'm no longer considered the strongest in Academy City. This, despite the fact that I'm still a Level 5 and that my powers haven't changed. No matter how many times these idiots never learn."
- Accelerator: "What exactly has changed in me?"
- Last Order: ""Someone will cry for Misaka if Misaka were to die, that was what Misaka was taught" "That's why Misaka will not die anymore." "None of us are allowed to die anymore, " concludes Misaka as Misaka concludes" -said to Accelerator.
- Last Order: ""Let's assume Misaka said she didn't want to fight anymore, what would you do?" discourses Misaka as Misaka discourses on a decision in the past." -said to Accelerator.
- Yoshikawa Kikyou: "Pick your poison." -said to Accelerator, regarding which choice he wants to make: find Amai Ao or secure Last Order.
- Accelerator: "You're right about that. It's obvious to anyone which one's the right one to pick." -said to Kikyou regarding his choice.