Ginoza and his team theorize that a mastermind might have influenced the murderous actions of two recent suspects by essentially providing them with the ability and motivation to carry out their deadly desires. Kogami sees eerie similarities between these cases and the earlier unsolved case that got him demoted to Enforcer which also resulted the grotesque death of his Enforcer, Sasayama. Meanwhile, Akane seeks out more information on Kogami from Kagari and Shion Karanomori and learns about Sasayama and the cold case known as the Specimen Case. At a girls' school, Rikako Oryo, the enigmatic president of the art club, ensnares an unsuspecting victim and mutilates her corpse into a work of "art" under the tutelage of the evident mastermind, Makishima.

With his profiling skills, Kogami determines that the girls' school killer isn't the same murderer from the unsolved case years ago; he explains that the recent murders lack "originality" and pointed social commentary of the previous killings. When he and Akane realize the culprit is one of the students, they locate Rikako - who escapes when one of teachers stops Kogami from executing her. As the Enforcers try to locate her secret routes and hiding places, Rikako flees - but not before everyone discovers her latest creation. Makishima calls Rikako to tell her that she's a disappointment and has Senguji dispose her. In the meantime, Kogami picks up a damaged audio file which was deliberately left by Makishima. Due to Rikako's failure, Makishima develops an interest in Kogami.