"It seems extremely similar to a certain otherworld I'm familiar with.""A certain shrine with a big torii""A bamboo grove that leads people astray, an upside-down Japanese castle""Villagers walled in by nature, the children from the temple school""A religious war, the wrath of youkai and gods...""A rental bookshop flourishing with not even any e-books, and no air-conditioning anywhere.""It was all in a dream, but the world was all real.""I myself am someone researching the occult. It was a total coincidence that I listened to this show.""Wanting to turn that coincidence into certainty, I sent you this letter.""It's about the otherworld in Swallowstone Naturalis Historia that was mentioned on the show."