"Investigation" (捜索 Sōsaku?) is the 57th chapter of the Toaru Kagaku no Railgun manga series.
Uiharu Kazari wakes up next to a sleeping Misaka Misuzu and realises that the two of them are in the Judgment infirmary. She gets up to look for someone else. She overhears Saten Ruiko and Shirai Kuroko discussing how Shokuhou Misaki had been manipulating her (Uiharu). When Saten says to keep this a secret, Uiharu reveals her presence to them and asks what they're talking about. Kuroko decides to explain the truth, reasoning that Uiharu is strong enough to handle it. After the explanation is done, Kuroko asks Uiharu to join in the investigation as they need her computer skills.
In the conference hall, the lights have been turned off and Misaki's mind control has caused the security guards to fight among themselves. Misaka Mikoto, dressed in a guard's uniform, encounters a guard. The guard is suspicious of her but (unknown to him) his mind is being read by Misaki. After the guard is incapacitated, the two Level 5s meet up. Misaki hears from one of the guards under her control that Kihara Gensei has been captured.
Back in the Judgment office, Uiharu and the others finally track down the person who'd taken Uiharu and Misuzu hostage: Kouzaku Mitori, a former student of Kirigaoka Middle School who had been sentenced to juvenile hall after an attempted terrorist attack. They plan to check the Bank's control centre for more information.
Mikoto and Misaki are led to a restrained Gensei.
Since she can't enter the Bank's control centre (not being a member of Judgment), Saten wanders around in the streets. She encounters Kamijou Touma, who is taking part in the item borrowing race event. Touma asks if anyone has a protective charm and complains about having to find such a thing in the city of science.
- Mikoto and Misaki seemingly manage to capture Gensei.
In order of appearance:
- Uiharu Kazari
- Misaka Misuzu
- Saten Ruiko
- Shirai Kuroko
- Misaka Mikoto
- Shokuhou Misaki
- Kihara Gensei (referenced only)
- Kouzaku Mitori (referenced only)
- Kamijou Touma