A curious young man named Kousaka Naoto is studying folklore at university. One day in July, just before a long summer vacation, he receives a letter from his missing mentor. Intrigued by the contents of the letter, Naoto decides to visit the infamous Kamimori village as part of his fieldwork. The village is located deep in the mountains and can only be reached by a bus that runs once a day. On the bus, Naoto meets a beautiful girl named Suou Serina, who was born in Kamimori but left the village as a child due to a certain incident. Serina and Naoto stay at the Suou residence, and as they spend more time together, their relationship gradually grows closer.