In a modern society in which violent crimes are on the rise, there is a team that tries to resolve cases without bloodshed. It is the metropolitan police's special team, known by the abbreviation SIT (Special Investigation Team).

The SIT doesn't get into action after a case but heads to the site just as a crime is being committed. They are on the front-line of risky missions, facing off against criminals; tenaciously conducting negotiations with criminals. As a result of the rigid police hierarchy that can curb the conduct of negotiators, the SIT is also a male-dominated society controlled with strict discipline. There is one female negotiator, Usagi Reiko, who bravely fights at the frontline. She is isolated in the male world of the SIT but courageously fights against crime as well as her organisation.