Heihachi Hiratsuka is loud and impolite, but always smiles. He is a strange detective. Unlike Heihachi, Kosuke Saionji is the heir of a wealthy family. He is full of justice, naive and honest almost to a fault.

Kosuke Saionji is then designated to the #1 investigation team, which he has always admired. Unfortunately, his job is to watch over Heihachi Hiratsuka. Up to this point, Heihachi Hiratsuka has been the sole member of his team, but he manages to solve all of his cases one by one. Other detectives are curious about his methods, some even think he may have some mystic powers. This is the primary reason why Kosuke is tasked to watch over Heihachi. The real reason Heihachi is able to solve so many cases is that the criminals hate Heihachi the most ....