The game is built around the Hanako-san legend — one of Japan's most widespread school ghost stories. Hanako-san is said to be the spirit of a young girl from the World War II era who haunts school bathroom stalls. The ritual goes: go to the third stall in the girls' bathroom on the third floor, knock three times, and ask "Are you there, Hanako-san?" A small voice will answer, "I'm here." Entering the stall, you may find a girl in a red skirt. The legend has been a rite of courage in schools for generations.