While Shirai frets about Misaka staying out again all night, she receives a visit from Kamijo, who manages to find Misaka's documents about the project. Kamijo catches up with Misaka on a bridge, where he tries to talk her out of doing anything rash.

Kamijo races to the scene of the experiment, only to find that it has already started. Kamijo calls out Accelerator, who takes him to be yet another challenger to his position, until for the first time, as Misaka watches on, he gets his nose bloodied.

Misaka stands up for clone #10032, declaring that she is doing so because they are sisters. The next day, the two of them spend time in a park, where 10032 asks her for a special favor. Later, Misaka has difficulty trying to express her thanks to Kamijo.

Finding herself face-to-face with a clone of herself, Misaka ends up helping her get a cat out of a tree, sharing ice cream cones, and having tea with her. It isn't until later that Misaka discovers the true, sinister project that calls for her clones.

Kozaku uses Exterior to make her way into Mikoto's mind, convincing her to attack the building without windows. Before she can go after Gensei, Shokuho must contend with Kozaku's puppet, until help arrives from an unexpected source.

Kamijo and Sogiita find that at best, they can only slow down Mikoto's transformation. Kuroko continues to search for Kozaku while dodging her puppet. Gensei pursues Shokuho for the access code that will let him unlock Exterior's potential.

Gensei has fallen victim to Shokuho's cunning, but Mikoto is still struggling to contain her power. Kamijo decides that he must help her at any cost.

Misaka lashes out at Accelerator, but is left frustrated. She realizes the full breadth of the situation she has become involved in, and feels responsible for allowing it to happen. Nunotaba discusses the ramifacations of the clones' existence with Misaka.

Misaka manages to sabotage most of the experimental facilities remotely before she is cut off, leaving her to deal with the rest in person. Shirai resolves to help Misaka by doing her part to be more vigilant at work, but risks shutting the others out.

The members of the underworld organization ITEM finish one mission, and are called in to defend the remaining facilities. When Misaka tries to infiltrate one building, she encounters Item member Frenda. Meanwhile, Nunotaba drops in at the other facility.

As Misaka continues her way into the research facility, she and Mugino play a game of cat-and-mouse. Meanwhile, at the other facility, Nunotaba sneaks into a control room, planning to disrupt the experiment by adding a new factor to the Misaka Network.

Having realized who Misaka is, Mugino decides to give her a run for her third-place ranking. When Frenda mistakenly leaves her doll-bombs behind while heading to the other facility, Misaka collects them and uses them to supplement her diminished powers.

Misaka and Kamijo meet again at the malfunctioning vending machine in the park, where Shirai mistakes him for being Misaka's boyfriend. Misaka becomes shaken when she bumps into another Misaka clone, and learns that the experiments are still ongoing.

Thwarted in her attempt to sabotage Tree Diagram, Misaka takes her frustration out on a nearby lab that is part of the project. Meanwhile, Accelerator and #10031 carry out their experiment, while Kamijo searches for Misaka's missing sister.

Shirai, Konori, Kongo and friends, and Uiharu and Saten confront the powered suits at the four Assembly sites, where they soon receive backup. Misaka and Febrie move to take on Aritomi directly, but he has one final surprise up his sleeve for them.

Shokuho and Mikoto find themselves in a traffic jam, and Shokuho demonstrates a tremendous example of her ability. The background behind the Exterior project is revealed, as well as Shokuho's connection to one of the original Misaka clones.

A young Kozaku grins and bears her way through her youth in an Academy City research institution, where she befriends Dolly, one of the other girls there. But when Kozaku learns the grim truth about Dolly, it sets her on a life-altering course.

Academy City's Daihasei Festival is approaching, and the festival's steering committee is charged with recruiting at least two Level 5s to take the athlete's pledge during the opening ceremonies. However, getting volunteers proves to be a challenge.

Frenda and Saten find themselves under fire from an unknown assailant, and duck into a department store to find cover. When none of Frenda's usual tricks seems to work against their pursuer, she has no choice but to resort to drastic measures.

Mikoto and Kuroko get in trouble for using their powers in the dorm. Their punishment: pool cleaning duty! Later, Kuroko finds herself feeling frisky after accidentally ingesting a powerful aphrodisiac!

Awkwardness ensues when Mikoto runs into Kamijo. When they meet again later in the day, Mikoto demands a duel! She gives it her all, but there’s a chance she’s no match for Kamijo’s powers.

Therestina reveals new information about her real identity and her master plan. Meanwhile, Kuroko and the gang vow to fight alongside Misaka in order to save the children jeopardized by Therestina’s activities.

Misaka and her friends reach the facility where the children are being held, but Therestina uses Capacity Down to take the Espers out of the fight. With everything on the line, it’s up to Saten to save the day.

As the Daihasei Festival begins, Uiharu and Saten enjoy themselves, while Kuroko sees to her Judgment duties. Mikoto and Kongo run an eventful three-legged race against teams from other schools. A plot involving MEMBER begins going into motion.

The Tokiwadai team competes in the Balloon Hunter event, but due to a case of mistaken identity, one of the Sisters substitutes for Mikoto. Yoshio Baba feeds the other school's team with data on the Tokiwadai competitors, with surprising results.