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, more like a secret base.Isagi Yoichi, the guy you thought is just a normal café barista is actually a secret agent and a dangerous person that can be really cold and psychotic crazy. The café has already been running for 4 years. And he's under an investigation of a wanted high class criminal around this small neighborhood. Isagi is a skilled professional agent. You probably wouldn't believe that this sweet guy who often flirts to get your attention can be a brutal guy who just shoots people with no mercy or best them up till they don't wake up anymore. That's what he is.