Sasagawa Suiren. She is a cute little girl with golden twin-tail hair and a stuffed rabbit on her chest. Her true identity is that of a former yakuza clan leader (45 years old)! And her temporary older brother Soji Sasagawa, who lives with her, is the mysterious swordsman who made Water Lily look like this two years ago (wearing a fluffy knit and a oversized hoodie). We call him the "wolf-faced watchman wolf"! The dark city of Osaka is ruled by numerous antisocial forces. The real Souji, however, is an ordinary, timid high school student. For the sake of those they are supposed to protect, the elder brother (a high school student) and the younger sister (a former gang leader) take on the evil that is spreading in the city. This is a chivalrous suspense action of the strongest uneven duo!