[Machine Translation] ( Under the fireworks, I confess to Black Cat ) It is June of my senior year of high school. The head of the game research club suggested that we go on a research camp during the summer vacation. At first, Kurokono did not intend to participate, but with the support of his father and sister, he decided to join the camp. Once the camp started, I, together with Kuroko, enjoyed chatting with Akagi and his siblings on the bullet train, watching the sunset on the deck of the ferry, taking an open-air bath, having a test of one's courage, and enjoying fireworks. We spend the best summer vacation on a remote island full of nature. During these days, we meet a girl who calls herself Yu Makijima. Yuu, who is well versed in fortune-telling and the occult, gets along well with Kuroko, and asks her to accompany him on an expedition to investigate the "Tennyo lore" passed down on the island. There we have a strange experience.