قسمت 6: کارآگاه بزرگ کوئیکو جنایتی را در جزیره تفریحی بررسی می‌کند

6

"Has an appearance of a young boy, with a mind full of grey matter. He is the great detective, Koikku!" For the shooting of Gravi and Procella's promotional video, both groups are at a resort island! From enjoying marine sports to a beach volleyball showdown, both groups are having their fill of the island and summer! With the shooting going as planned, all that's left now is free time... when a tragic crime has occurred! Without so much as a single lead on who committed the crime, Koi,claiming the title "the Great Detective Koikku", has set out to solve this crime! Will Koikku discover the one and only truth!? (Source: Tsuki no Uta Wiki)