"August 15, Part 3" (八月十五日③ Hachi-gatsu Jū-go-nichi ③?) is the 23rd chapter of the Toaru Kagaku no Railgun manga series.
The chapter opens with Misaka 9982 announcing to Accelerator (Who's cracking his neck to warm up) that the experiment is going to begin. As she's fighting Accelerator, the bullet ricochets due to his power and hits Misaka 9982, causing her to run into an alley.
At the same time Mikoto finds out about the 'Level 6 Shift' program with the Accelerator (Given to her by Kazari) and that the scientists are killing the 'Sisters' in order to Shift Accelerators Esper Level to 6. At first she thinks its a bad joke, but after given the location from the report, she can't help but check if it's real. Upon arriving, she doesn't find anyone, but she finds Misaka 9982's NV Goggles shattered on the floor.
The chapter cuts to Misaka 9982 being chased and attacked by Acclerator. Knocked to the ground and bleeding, Misaka 9982 states that she doesn't know what ability the Accelerator is, but concluding that his feet are unprotected, reveals there is a mine underneath. The explosion is repelled by Accelerator, who shoots out of the smoke to grab onto Misaka 9982's leg, ripping it off which causes the Gekota badge to roll of. She doesn't stop moving, instead starting to crawl away, much to the disgust of Acclerator who tells pauses before saying "Enough already, you". He starts picking up a train and throws it at Misaka 9982, just as she stops crawling to pick up the Gekota badge that rolled off before.
The explosion the mine causes attracts Mikoto to hear the explosion and she runs to the bridge above where they were fighting. She sees Accelerator picking up the train and throwing it at Misaka 9982 (As Misaka 9982 picks up the badge). The chapter ends with Mikoto screaming, running towards Accelerator in a rage.
Adapted from? which chapter of novel
refs to previous chapters