Isagi Yoichi is a cafe owner in a small neighborhood. He's a secret angent on a mission. He owns a cafe because it's a part of the mission that he's on. Isagi Yoichi, the guy you thought is just a normal café owner is actually a secret angent and a dangerous person that can be really cold and psychotic crazy. The café has already been running for 3 years. And he's under an investigation of a wanted high class criminal around this small neighborhood. Isagi is a skilled professional agent.