Living in Ikebukuro — an area infamous for juvenile crime, 21-year-old Makoto Majima becomes associated with a youth gang called the G-Boys. A troubleshooter known for his cool headedness and ability to get things done, Makoto diffuses tense situations around Ikebukuro to keep his friends and others out of harm's way. However, the mysterious death of his girlfriend and an escalating gang turf war threaten to be more than Makoto can handle.
When a popular anchorwoman for a prime time news show becomes the suspect in a murder case, her estranged husband - who has worked as a prosecutor in the past but now works as a public defender - decides to defend his wife.
The Mobile Investigative Unit (known as "MIU") of the Tokyo Metropolitan Police Department attempts to solve cases within 24 hours. Detective Kazumi Shima is selected as a new member of MIU. He is intelligent, with excellent observation and communication skills. Yet, he does not trust other people. He is unable to find a partner in MIU and is ordered to partner with Police Officer Ai Ibuki, who works at a police substation. Ibuki applied for MIU, but he failed. He is in excellent physical condition, but he lacks knowledge and experience as a detective. Shima learns about Ibuki's background and he becomes more nervous. Finally, Shima has his first meeting with Ibuki.