The moment the culture festival reached its finale, the jewel object made by Shirogane was stolen by a phantom thief who calls himself Arsène. Kaguya and the others headed to the roof where the phantom thief keeps appearing, but there was no one there. Fujiwara, who transformed into a genius detective, struggles to solve the mystery behind the calling card and uncover the thief's true identity. But Kaguya, left behind at the scene of the crime, had begun to figure out the criminal. The problem is the location. Kaguya traced the phantom thief's line of thinking and headed to where he is now...
Just when I was about to summon
all my courage and take the plunge!
!بعد أن أوشكت استدعاء شجاعتي واتّخاذ القرار
J-Jetzt, da ich endlich den Mut
gefunden habe und mich trauen würde …!
Ahora que me había decidido
a tener valor…
Ahora que me había decidido
a tener valor…
Dire que j’allais enfin
prendre mon courage à deux mains !
E-E io che ero finalmente riuscita
 a farmi coraggio per questo...
Agora que eu tinha
decidido ter coragem...