Jailbreaker Arc

Jailbreaker Arc (ジェイルブレイカー編) is a story arc in the Toaru Kagaku no Railgun manga series, covering chapters 98 onward.

The story focuses on a jailbreak trial organized by the operators of a new private juvenile hall in Academy City in order to test the facility's security features. The challenge is to break into the facility and successfully extract the prisoner, with a one billion yen reward for successful completion.

The New Juvenile Hall
The new juvenile hall was the second such facility to open in Academy City, but unlike the publicly-run Reformatory, this juvenile hall was run by a private security business. It was built in response to a rise in crimes committed by espers as opposed to those involving Skill Outs and a belief that the private firm could provide a better service than the publicly-run facility.

The Jailbreak Trial
In order to promote the new juvenile hall and test its security features, Director Kyougoku invited interested espers to challenge the facility and search out vulnerabilities. The objective of the challenge was to break into the facility, find and retrieve a target prisoner, and then break out of the facility with them. The reward for successfully completing the challenge was one billion yen.

During an interview accompanying the announcement, Kyougoku boasted that his company had built defenses to hold even a Level 5 and that even if the likes of Tokiwadai Middle School gathered all of their students, he doubted they'd even breach the first wall. This prompted several Tokiwadai students to enter, including Misaka Mikoto.