After getting Natsuki hurt when a small dog barks at them, Ryoku questions if he is useless to Natsuki and gets depressed. Moping by himself, Ryoku finds a partitioning screen in Natsuki's house which has a powerful dragon and a tiger drawn on it. According to Natsuki's grandfather, the dragon and tiger are said to have been rivals, fighting for the position of the strongest in the world since olden times. Hearing that, Ryoku is determined to become a powerful dragon that can protect Natsuki and begins to train. However, the next day, upon hearing a loud noise from the room with the screen, they take a look and find a huge hole where the tiger was. Natsuki and Ryoku both find this strange. Truth is, there is a legend that the tiger drawn on the screen sometimes jumps from the screen and prowls around.