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.

As Yomikawa takes over investigating the runaway security robots, Konori invites the whole gang out to take in a bath at a bathhouse. On their way home, a number of detours lead them to a confrontation with yet another, much more dangerous runaway robot.