The Metropolitan Police Department has newly established a fictitious specialized department "Finger Murder Countermeasures Office" = Yubitai, which aims to solve problems and incidents caused by slander on SNS. The members are all strangers who have one habit and two habits, including Banjo Wataru. At that time, the parents of the model Sanada Kozue, who committed suicide suffering from slander, visited and complained with tears that her daughter was killed by the heartless words of anonymous humans. Upon hearing that, Usui Sakiyoshi, a new detective, promises, "I will definitely arrest the criminal!"