Keiji 7-nin

Satoshi Sakashita (Nozomu Kotaki) and Takumi Nonomura (Jin Shirasu) climb the mountains of Okutama in order to deliver belongings to the bereaved family. This memento is Sachi Koyanagi (Ryoka Morita), who died six months ago when he went on a night hike with his college circle friends to see the sunrise, and on the way he slipped off the mountain trail and hit the back of his head. ).
Before long, Michitoshi and Takumi arrive at a mountain villa owned by Tetsuo (Yoji Tanaka), Sachi's father and a mountain photographer. After her daughter's accident, she says she is spending time alone at this mountain lodge, where cell phones are out of range. The two are welcomed into the room, but Michitoshi notices evidence of a rain-soaked umbrella left at the entrance and traces of ashes from burning incense a little while ago. Is there anyone other than Michitoshi, Takumi, and Tetsuo at the villa?
Michitoshi leaves behind saying, 'If I don't go back, Takumi-san will go outside,' and begins investigating the inside of the villa on his own, but is caught by Tetsuo with a hunting gun. With a hunting gun pointed at the back of his head, he is taken to a room where five members of Sachi's university circle are locked up...!? . Michitoshi was amazed at the useless Takumi. On the other hand, Yu Amagi (Kiyuki Higashiyama) is concerned about Sachi's accident documents, so he goes to Shuntaro Domoto (Kinya Kitaoji) who was in charge of the autopsy. Originally, it was not a case that an autopsy would have been carried out, but it was carried out at Tetsuo's strong request. Tetsuo thinks Sachi's death wasn't just an accident, so he's resorting to brutality...!? I was asked what was left...
Tetsuo reveals that it is impossible for Sachi, who has been familiar with the mountains since he was a child, to fall, and that he has also discovered certain 'evidence', and orders the five circle members to discuss and find the culprit. The time limit is 3 hours. Furthermore, he declares that if the culprit is not found, he will set fire to the villa.
Michitoshi searches for a way to escape, and Takumi utters a pitiful voice, 'If only Amaki-san was here.' And Amagi, who is worried about the safety of Michitoshi and Takumi, arrives at a certain truth from the materials of the accident...!?