Hiroshi Inaba (voiced by Junichi Tomobu) was originally a police dog. He was bred through special means and has a human-like appearance and a beast-like sensitive intuition and movements. At present, Hiroshi Inaba runs his own firm and works as a private detective. He has only one purpose in doing all this - to find his missing brother Haruka Inaba (voiced by Mizuki Saiga). Under the influence of his old partner Kuniharu Ogino (voiced by Tomoyuki Morikawa), Hiroshi was inexplicably involved in the dispute of the Italian Mafia. In order to eradicate their huge ambition to control Japan, Hiroshi brought his two young assistants Kei Nozaki (voiced by Miyu Irino) and Yuta Sasaki (voiced by Asami Shimoda) to fight against the evil Valentino family together with Ogino. At the same time, in the Mafia organization, Hiroshi accidentally discovered the whereabouts of his brother. What kind of conspiracy is hidden behind this?