Yuzuru Hamura is a university student and a fan of mystery novels. Against his will, he was forced to join the school's mystery club. The club is led by Kyosuke Akechi. Meanwhile, Hiruko Kenzaki appears in front of them. She attends the same university and she is also a private detective. These 3 people attend a summer camp and stay at Shijinso pension in the mountains. On their first day there, they must barricade themselves in the pension. The next morning, they discover a murder has taken place in the pension.
| Actor | Role |
|---|---|
 Ryunosuke KamikiYuzuru Hamura | Yuzuru Hamura |
 Minami HamabeHiruko Kenzaki | Hiruko Kenzaki |
 Yuki FurukawaHaruya Tatsunami | Haruya Tatsunami |
 Tokio EmotoKanemitsu Nanamiya | Kanemitsu Nanamiya |
 Riko FukumotoReika Hoshikawa | Reika Hoshikawa |
 Eri FuseRin Takagi | Rin Takagi |
 Shono HayamaAyumu Shindo | Ayumu Shindo |
 Tetsuhiro IkedaYuito Kanno | Yuito Kanno |
 Tomoya NakamuraKyosuke Akechi | Kyosuke Akechi |
 Yui SakumaSumie Nabari | Sumie Nabari |
 Muga TsukajiTobio Deme | Tobio Deme |
 Anna YamadaKirei Mifuyu Shigehara | Kirei Mifuyu Shigehara |
 Yuma YamotoMitsuru Shigemoto | Mitsuru Shigemoto |
 Reika OozekiTakako Kudamatsu | Takako Kudamatsu |