After experiencing a traumatic incident 8 years ago, driven by his desire to protect lives and keep those things valuable to others from being taken, Saikawa Naitou joins the Golden Agency - a security agency that service unarmed bodyguards that are called KEEPERS. With his strong will and super observational skills, Naitou along with his partners Kimiko Aimiya and Asayama Shinichi, work together to achieving the success of every mission.