Yuri Mito is the only son of the local priest at Yachimata Shrine. During spring break, he encounters Kikuramikami no Hime — the guardian of a mystical relic kept in the woods near his school. She explains the long and strained history between humans and the Tayutai, a mythical race that was sealed inside the relic because of the danger they represented. To bridge the worlds, the goddess reincarnates as a young girl named Mashiro and places herself in Yuri's care. Then the relic is accidentally destroyed, releasing the Tayutai — including the Three Mightiest, the most dangerous of them all. Drawing on spirit powers that run through his family line, Yuri teams up with Mashiro and three other heroines to answer the question the relic's destruction has raised: can humans and Tayutai actually find a way to coexist? A romantic fantasy adventure built around growth, connection, and the mysteries of what it means to love.