USA, 1949... Kevin Yamagata, an American of Japanese descent, is the creator of the comic bestseller "Billy Bat." The main character is a bat - the comic is a stylistic mix of classic Disney and superhero comics. Suddenly, Kevin learns that the bat character has supposedly existed in Japan for a long time. Did he not actually create "Billy Bat" himself? In search of an explanation, the comic artist embarks on the greatest adventure of his life. And not only does everything he has known turn upside down, but the bat also seems to have power over all people across all times.