The series takes place in the year 2030, where many people have become cyborgs with prosthetic bodies. Primarily set in New Port City (新浜市, Niihama-shi), in the fictional Japanese prefecture of Niihama (新浜県, Niihama-ken), the series follows the members of Public Security Section 9, a special-operations task-force made up of former military officers and police detectives. While the group investigates various crimes, both seasons feature ongoing investigations into two incidents that embroil the group in corruption within other branches of the Japanese government.