Tree Diagram Remnant Arc

The Tree Diagram Remnant Arc is a story arc in Toaru Majutsu no Index. Focusing mostly on the point-of-view of Judgment member Shirai Kuroko, it deals with an important piece of the recently destroyed Tree Diagram, the Remnant, being stolen by Musujime Awaki a fellow teleporter, as well as Misaka Mikoto and her clones' struggle to stop the experiment from happening once again.

Tree Diagram

 * Main article: Tree Diagram

After Index unknowingly destroyed Tree Diagram back in the 28th of July, the knowledge of it's destruction was seemingly kept secret by Academy City. However, it became quite apparent with that Academy City could not keep it's demise a secret any longer; such as the inaccurate weather predictions, as well as at some point several countries with space programs, desiring to seek out the remains of the destroyed super computer with under the cover of "showing-off" their space programs to the world, and to prove their reliability to sponsors.

Despite the other countries' efforts, Academy City's space program based in the 23rd School District was successful in recovering the Remnant of Tree Diagram, and hired people from the outside of Academy City to deliver the Remnant, that was encased in a radiation-proof, air-tight luggage bag made out of silicorundum to the Tokiwadai Middle School Subsidiary Calculus Facility, a code to hide the true recepient of the Remnant. Meanwhile, Awaki Musujime – the guide to the Windowless Building – is assigned by the Science Association to retrieve the Remnant, with this her mission she also receives voluntary aid from her comrades as well.

Other Factors
Meanwhile, both Mikoto and her clones discover that the Remnant has been recovered, and have become worried that the experiment would restart if ever the Tree Diagram would be reassembled as the result of Remnant's recovery. Due to this they started individual efforts in hoping to stop it from occurring again, with Last Order – the administrator of the Misaka Network – giving full support to the clones' attempts to stop it.

Yomikawa Aiho, the guardian of Accelerator and Last Order is later called to mobilize her unit to stop the Science Association's actions.

Prelude
Kuroko notices Mikoto's unusual behavior, during their shopping of lingerie after seeing the news report regarding the recent influx of countries with space programs launching missions into space, with Academy City launching their rocket last week, though it was later completely disregarded and they returned to do their shopping. Kuroko is later called by fellow Judgment member Uiharu Kazari regarding a recent and unusual robbery, much to Kuroko's dismay since she rather spend time with Mikoto. Before leaving, Mikoto advises Kuroko regarding the weather, saying that it might rain later on, which Kuroko finds both unusual and suspicious.

Kuroko later arrives at the Judgment 177 Branch Office where she is briefed by Uiharu Kazari about the robbery. Looking, at a video recording, the robbers have stolen a luggage bag and later realize that both the victims and culprits of the robbery have suspicious backgrounds. Kuroko later decides to hunt down the culprits instead, as it was more convenient for her as a recent electrical outage which caused a traffic jam, has forced them to divert their escape to underground as well as the victim of the robbery being unable to be contacted. It was also more convenient for her, as a single unit to confront the culprits rather than an entire team of Anti-Skill members, as they are unable to reach the scene on time due to the traffic jam, as well as the difficulity dealing with procedures in order for them to take quick actions. Toaru Majutsu no Index Light Novel Volume 08 Chapter 2 Kuroko quickly leaves to pursue the culprits, with Kazari backing her up by helping her locate the targets.

Battle in the streets
With Kazari's help, Kuroko was able to find the culprits and the luggage bag easily. With the culprits general lack of knowledge regarding the espers of Academy City, Kuroko was easily able to defeat several of the armed men and acquire the luggae back easily, forcing the others who witnessed dominance to flee. In the light novel, Kuroko was able to defeat all the men.

Kuroko would later get a call from Mikoto, originally wanting to ask her if she could cover for her when the Tokiwadai Dorm Supervisor would begin her inspection of the students in their rooms, as she has other matters to attend to, though seeing as Kuroko is still working, she would ask one of her kouhais instead, ending her call immediately afterwards.

Teleporter vs. Teleporter
Kuroko's later falls to her back after the luggage bag that she took from the robbers, which she was sitting on, was teleported away from her, and is immediately followed by a corkscrew being teleported into her shoulder. Despite being in terrible pain, Kuroko is able to see the face of her attacker who is now sitting on the luggage bag. She tells Kuroko (which she apparently knows) that she is a teleporter as well, although she can teleport even without contacting the object being teleported. Kuroko tries to attack the girl with her needles, however, the girls quickly teleports the unconscious bodies of the outsiders Kuroko just defeated to block her view.

However, Kuroko still teleports her needles to hit the girl (since teleportation is point-to-point movement and not linear), however, Kuroko missed entirely as the girl moved a few paces backwards utilizing the weakness of teleportation being point-to-point (points cannot be changed by the teleporter after teleportation). The girl takes one of Kuroko's needles and throws it towards her as a projectile, with no where else to go, Kuroko teleports forward trying to land a blow on the girl, however, the girl predicted this and is able to teleport a needle into Kuroko's body, disabling her momentarily.

The girl then mocks Mikoto for being desperate enough to involve Kuroko, her underclassman (kouhai) into her business. Hearing the girl mention Mikoto's name, Kuroko demands to know answers from the girl. Seeing Kuroko's ignorance, the girl reminds Kuroko on how a traffic jam just so happens to occur when her men were stealing the luggage bag, implying to Kuroko that Mikoto was somehow involved due to the nature of her power. This confuses Kuroko, though the girl gladly fills in the blanks, stating words such as "Remnant" or "Silicorundum". The girl says that what she is sitting on now is the Remnant of the Tree Diagram, the supercomputer installed on the Orihime-1 satellite that was destroyed. Kuroko is unable to believe this, stating that Tree Diagram should still be in orbit above the Earth's atmosphere. However, the girl pulls out photographic evidence, showing the scattered remains of the satellite in the vacuum of space; the girl reasons why people would want the "remnants" of the supercomputer, and mocks Mikoto's helplessness in the situation, seeing that her nightmare regarding the experiment is finally over since someone destroyed the Tree Diagram, but now people want to rebuild it again, which would mean the experiments would restart.

Seeing Kuroko is still confused, the girl mentions August 21st (the day Touma defeated Accelerator) and teases Kuroko if she could find the truth regarding what happened in August 21 the she would become friends with Kuroko. Seeing an opening, Kuroko quickly tries to draw up her skirt to touch one of her needles, this however, did not work, as the girl was too quick for Kuroko and pierced her again with one of her own needles , she later leaves with the luggage bag.

Trivia

 * With only two episodes, this is the shortest arc the anime adaptation of the novels has featured.
 * This marks the first story arc where nearly the entire narration is not in Touma's perspective, the first arc that featured this was with Accelerator in the 5th Light Novel Volume story arc where he shares the narration with Touma. Accelerator would not get an entire story arc centered around his perspective nearly entirely until the 15th Light Novel's story arc.