The students investigate Mr. Momoya's past and discover that Shiro had died in a car accident, suspecting that his death may be related to Mr. Momoya's sacrifice to the Sphinxes.

Yurio solves one of Dactyla's puzzles, returning everyone to the third dimension.

Junpei admits that he gave the Sphinxes an unsolvable puzzle, causing them to self-destruct.

The four students hear rumors that Spudio is inside their high school, which is abandoned and due to be demolished.