9 no Puzzle to Mahou Tsukai9 no Puzzle to Mahou Tsukai (Wiseman) ; 9 no Puzzle to Mahoutsukai ; 9 no Puzzle to Mahoutsukai (Wisman) ; 9 no Puzzle to Wiseman ; 9のパズルと魔法使い

In the near future, a BCI controller that reads your brain signals and makes your conscious 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 sister-in-law, Rin. However, at the request of his adoptive father, Katsuro investigates Internet crimes in exchange for reduction of his punishment.