9 no Puzzle to Wise Man In the near future, a BCI controller that reads your brain signals and allows your consciousness to dive into the virtual world of the Internet has become extremely popular. Katsuro, who was arrested for a certain crime, was adopted by police officer Yumeji and serves his prison term while living with his adoptive sister, Rin. However, at the request of his adoptive father, Katsuro investigates Internet crimes in exchange for reducing his punishment, bit by bit.