Pursuing the mystery of the poem by the "Goddess of Silence," the pair head to Gokurakuji Temple to meet with the few people who had contact with the previous owner, hoping to find some clues. Although they don't get a proper answer, it appears that the Clock Tower was built after being commissioned to design by Nakamura Seiji, who was a close friend of the previous owner at the time. Shikatani and Fukunishi return to the Clock Tower to hear more about the building and clock tower in the backyard. Meanwhile, inside the old building, another participant is killed by an unknown assailant. The remaining members become suspicious and suspect that the culprit may be among them.

Together with the remaining members, Konan tries to face the mystery of what is happening inside the old building. As he recalls the tragedy that occurred at the Decagonal House, Konan, like Shikatani, comes to the conclusion that "if it's a building designed by Nakamura Seiji, surely there must be some kind of hidden trick?" and he desperately searches for clues. However, the situation continues unabated, and finally... Fukunishi, who was working with Shikatani, also tries to find answers to the "past events" by relying on fragments of his own memory.