The family of Kage Ryo, a top student in the law department, was torn apart due to a huge business fraud, but the culprits who were at large were still enjoying prosperity and wealth. When a black Death Note accidentally fell into his hands, Ryo Kagemiya did not become a universal "Kira", but transformed into a precise "executive officer". With careful plans, he "accidentally" eliminated those bugs at the top of society that the law could not touch. This series of unrelated deaths attracted the attention of the Metropolitan Police Department's genius detective Ru Yuexian. A battle of wits surrounding an invisible weapon begins. The balance of justice began to swing wildly between two extreme geniuses
