"August 15, Part 4" (八月十五日④ Hachi-gatsu Jū-go-nichi ④?) is the 24th chapter of the Toaru Kagaku no Railgun manga series, released on August 27, 2009.
The chapter opens with a flashback to a conversation between Shirai Kuroko and Misaka Mikoto, in which the former asked the latter what she would do if she met her own clone. Mikoto answered, with a smile, that she'd feel sick and want the clone to disappear from her sight.
Back to the present, Mikoto rushes towards Accelerator and attacks him, but is easily repelled. Mikoto is at first concerned, but then seeing Misaka 9982's leg on the floor, screams again and attacks him with numerous magnetized rails. Accelerator repels the rails towards Mikoto, which she dodges, and then he realizes this Mikoto is the original one. He says that fighting her should speed up this program and approaches her. Mikoto demands to know his motivation to participate in this program if he was already so strong, to which Accelerator replies that he wants 'absolute power', a power that makes other people laugh at the thought at fighting him.
Mikoto is disgusted at Accelerator's response and fires off her railgun at him, which he deflects once again. Disappointed that this is all she has, Accelerator starts advancing towards Mikoto, but is stopped by other Sisters, who tell him that the calculation might be thrown off if he fights against Mikoto. Accelerator introduces himself to Mikoto and then walks away. Mikoto's knees give out from fear. As the Sisters prepare to clean up the battlefield, Mikoto shouts at them, asking why they are willing to participate in this program. They reply that they are merely lab animals.
By order of appearance:
- Multiple Sisters, ranging from 9995 to over 10008.
- Electromaster - Misaka Mikoto, Level 5
- Iron Sand Manipulation
- Accelerator - Accelerator, Level 5
No new abilities were introduced in this chapter.
No new locations were introduced in this chapter.
- The flashback shows the end of the conversation that was not fully shown in Toaru Kagaku no Railgun Chapter 20.