The Special Investigation Team (SIT) is a high profile team of officers trained to handle cases in kidnappings, hostage situations, corporate blackmail, and other highly volatile criminal situations. Their goal is to prevent crimes before they take place.

Reiko Usagi (Ryoko Yonekura) is the first female officer to join SIT. At first she encounters difficulties in the male-dominated environment, but soon gains the respect of her fellow officers with her uncanny analytical skills and ability to stay calm in the most heated situations.