Eishi Karasuma is an average student who has only one friend, Mikasada Kamoda. He is smart and silently looks down upon the other students and does his best not to look like one of them. One day, he and Kamoda are on a bus ride home, with the only other passengers being Rei Sagisawa and Umino Tsubame. The bus derails and falls off a cliff, but everyone is miraculously saved, aside from the bus driver. While he and Kamoda are talking about how they might've survived, wings grow from their backs, and he discovers that he is the same kind as the Birdman that has been spotted around Japan.