Homura Roku is entrusted by Harube and Tsuko to investigate the mystery of Tagawa Isamu's disappearance. After learning the clues about Chihayakan from Tagawa's diary, they went to Tochigi Prefecture to search. There, they encounter an old woman's warning, but decide to head to Chihaikan. The building of Chihayakan is weird and they try to find the entrance and find that the power is out but there is still light and music. Then, they found a passage into the museum and entered the maze. In the maze, they found a strange goldfish tank and a mysterious door. Homura solved part of the mystery, and they continued to search for Tagawa's whereabouts. So, is Tagawa in the museum? Why did Gu Shenxingji become a vampire? What kind of secret does Tian Hezi have?
