Some time ago, Shunsaku Ban witnessed his friend’s murder during a random robbery attempt, and decided to become a guardian for the man’s infant son, Yuno. The child instantly bonded with a mysterious green cat that was carried by the gang, but Shunsaku was convinced that there’s something nefarious about the feline. Now, in the present, his long lost child surfaces in the news as a rich and powerful man who’s having the best luck at the casinos - and somehow, the green cat is still alive and at his side. Determined to save Yuno from the clutches of this evil creature, Shunsaku begins to investigate the truth of what’s really going on...