Time has passed since the Grim Reaper Murder Case that shook Konohana Academy, and the newspaper club — led by Momoi Meguru alongside self-appointed president Tachibana Miako — has returned to its normal rhythms. Then a former classmate of Meguru's arrives with unfinished grievances and challenges the club by founding a rival Mystery Detective Club. A fire breaks out in the basketball club room that same night. The student inside burns to death. As if mocking the investigation, murders follow in rapid succession — impossible to tell whether they are targeted or random. The school is under threat again, and this time a competitor is watching every move the club makes.