With the club recruitment week happening at First High School, Honoka and Shizuku, who are all-round outstanding students, are asked by various clubs to join. When they find themselves mobbed by club members, Eimi comes to the rescue, and the three of them become fast friends. One the way home from school, Honoka and her friends witness Tatsuya, who recently became a member of the Disciplinary Committee, being attacked by someone. Eimi, who is driven by her interest in this incident and in Tatsuya, decides to investigate who the attacker is. Honoka and Shizuku get pulled into Eimi’s investigation and the three girls end up forming the Girls’ Detective Club.