The chapter was released in 2 parts when serialized in Dengeki Daioh and combined together when compiled for the tankōbon version.
Part 1: Struggle to the Death (死闘 Shitō)
As Saten flees with the crowds, she recalls her conversation with Frenda prior to unleashing her plan, where she warns Saten that if she is taken hostage she will not hesitate to abandon her. Frenda tells Saten that as they live in two different worlds then she should forget she ever met her. However, Saten is adamant and reminds Frenda that she has bought a whole bunch of canned mackerel in case she came by to eat with her again, and that she will wait for her to take responsibility.
The battle continues and both seem to be evenly matched, with Rakko using her collapsible rifle and Frenda using her small bombs. However, Frenda can't throw them properly because of the damage she incurred from being shot by Rakko earlier. Rakko later kicks Frenda down and believes she has won. However, Frenda reveals that she has planted bombs all over the department store, and she would be much safer on the floor. With all bystanders cleared, Frenda pulls the trigger. As Rakko wonders when the bombs were planted and what she intended to do, she realizes that the bombs were thermobaric. Thinking quickly, Rakko tries to go toward a hole that was made during their battle. She jumps and tries to breathe in deep the fresh air. However, she was caught off-guard, and it is revealed to be a trap by Frenda, shoving small bombs into Rakko's mouth. With a kick, Frenda makes Rakko fall down, and with parting gifts from Frenda: more bombs. With that Frenda defeats Rakko after triggering the bombs, creating an explosion.
Back with Saten, she is in her school being questioned about her involvement in the incident. Uiharu Kazari notes that she still needs to be protected by Anti-Skill and Judgment just in case. Saten asks Uiharu about the department store, and Uiharu tells her that though there has been explosions and a battle, no bodies were found there. With nothing more to be said, Uiharu says that they should move now and that Judgment will provide everything for her. Saten then requests a new phone. At the safe house, Saten is dejected as she lies on her bed. However, she lights up when her phone gets a message. It is from Frenda who tells her that she'll meet her in a week to eat the mackerel she bought, making Saten happy.
Part 2: Regret (残心 Zanshin)
The members of SCHOOL gather together for a meeting. The leader of SCHOOL, Kakine Teitoku, thanks his team for going to the trouble of collecting information on the Tweezers using Indian Poker cards. Kakine begins to explain that the Tweezers will be used at a facility near Kirigaoka Girls' Academy in a few days but is interrupted by Yumiya Rakko, who is revealed to still be alive. Rakko, now wearing a mouth guard and eyepatch due to sustaining injuries from Frenda's bombs, demands to be able to hunt down Frenda but is silenced by Kakine who tells her to focus on the upcoming operation.
One week later, Saten is in her room waiting for Frenda to come join her for canned mackarel after inviting her on the Speech Bubble app. However, Frenda hasn't responded and appears to be late. Saten's doorbell suddenly rings and Saten quickly rushes to the door and opens it, expecting it to be Frenda. Instead Uiharu, now wearing a cast on her right arm, is at the door and has stopped by to give Saten a report on her protection status. A depressed Saten decides to invite Uiharu in for dinner, saying she made too much.
- Frenda Seivelun defeats Yumiya Rakko.
- Yumiya Rakko survives her fight with Frenda. However, she has sustained significant facial injuries.
- SCHOOL begins their operation for the Tweezers.
- Frenda fails to fulfill her promise with Saten.
In order of appearance:
- Sunazara Chimitsu (referenced)
No abilities were featured in this chapter.
No notable locations were introduced this chapter.
- Yumiya Rakko is revealed to be Level 0.
- Kakine Teitoku is formally introduced in the Railgun manga.
- The manga timeskips past the events that take place in Toaru Majutsu no Index light novel volumes 14, 15 and 16.
- Frenda's promise to Saten that she'll eat the canned mackerel she bought on her account from the last chapter is referenced here.
- References to Volume 15 of the Toaru Majutsu no Index light novels and the Battle Royale Arc.
- Yumiya Rakko, SCHOOL's original sniper prior to Sunazara Chimitsu survives Frenda's attack, creating an narrative consistency between this chapter and the original novel where both SCHOOL and ITEM acknowledged that the latter killed Rakko.
- Uiharu Kazari gains a cast on her arm, a reference to her run-in with Kakine Teitoku during the events of October 9 after she tried to protect the whereabouts of Last Order from him.
- Frenda utters "Ha det bra" as she delivers the final blow to Rakko. This is Norwegian language meaning "Good bye". Thus it appears that Frenda originates from Northern Europe, or has profound connection with there.
- As stated above, the contents of this chapter are combined from chapters 83 and 83.5 of the original magazine numbering to form a single chapter in the tankōbon version. However, there is no major change to the content of this chapter other than the numbering.
- Frenda: "Ha det bra!" -Frenda saying goodbye to Rakko just before blowing her up.