Through a series of monstrous disturbances triggered by the summer camp of the Occult Institute, Risa confronts her own abilities and begins to study and train as a demoness. Around the time of graduation, her career path has been decided. Miu, who has been studying the occult after retiring from club activities, plans a graduation trip. The destination is that abandoned school she visited in the summer. Risa joins the trip with Nanami, who becomes her best friend as they work together to solve the case.

The wooden school building is reborn as an accommodation facility. Asuka, a former advisor of the Occult Institute, is working as a curator at the facility’s local museum.

She tells him a story about the secrets of the mountain hoard. Thanks to Miu’s enthusiasm for the new information, the graduation trip turns into an occult investigation and research trip. Guided by Ayano, a fellow curator of Asuka’s, who is also involved in occult-oriented research, they tour the town’s ruins and spiritual spots together.

Risa and Nanami are worried about what will happen after the incident, but the town’s Asuka is also at peace and pats them on the back.

However, that night. Once again, Risa is caught up in a bizarre incident caused by a monster.