Yoshiki and Hikaru are two teenage boys living in a small town in rural Japan. Despite having opposite personalities and different hobbies, the two maintain a close friendship. However, on one winter day, Hikaru is fatally injured while hiking in the mountains alone. Before dying, a mysterious eldritch being comes across him and consumes him, becoming him physically in the process. This "Hikaru" has all the feelings and memories of the original, yet remains a separate being, something Yoshiki realizes rather quickly. Yoshiki still wants to stay with "Hikaru", however "Hikaru"'s alien nature, along with other eldritch beings and hunters of said beings may make that impossible.