During a VESPER staff review of Mahoro's life and activities following her entry into civilian life, a letter from Mahoro is read to the assembled officers. In it, she describes taking part in a "summer vacation group research trip" to explore the notorious "nine mysteries" of Hiryu School 4. Seven of these are generally acknowledged to be no more than standard rumors typical of any school; the remaining two, however, have not been as easy to put to rest. Of course what Suguru, Kiyomi and Toshiya don't know is that all through, the three girls, minus Mahoro, are playing them, as part and parcel of their own "human response to stress" research project. But seek, and ye shall find: it does not take much to send them running frantically through the school to get away from "red-haired Ando", according to legend, a girl who fell to her death from the school roof years ago and has been haunting the halls at night ever since. Mahoro herself is in on the joke, though she plays along. The twist, however, comes when, after becoming separated from the group, she comes across the real Ando, a ghost or spirit trapped in the school until she can confess her love to a boy whose own spirit is trapped in another part of the building. Reunited by Mahoro, the two ghosts, now freed - and together - disappear, and the letter concludes.
