Mihara Shouma is a first-year high school student. Shouma hasn't seen his good friend Atsushi in 3.5 years, ever since they lost contact with each other after elementary school. One day, Atsushi gets in contact with Shouma to invite him to a rare festival, so they can meet up and talk. Shouma goes to the "Tanabata Seven Night Festival" deep in the mountains, but Atsushi is not there. Instead, a girl named Shiori who also has a person she wants to meet is there. The festival's program manager Kanna suggests that he stay until the festival is over, and so Shouma and Shiori help Kanna prepare for the festival. Shouma and Shiori then get wrapped up in some strange events happening in the town.