Raku Ichijo (Kento Nakajima) is an only son and a high school student. His father is the leader of yakuza group Shuei-gumi. Raku Ichijo doesn’t like to fight and he…

The story takes place in a harbor town where a gloomy middle school student named Kai meets a mermaid named Lu.

Hiroya Munakata (Sho Aikawa) is the leader of the yakuza group Munakata-gumi. After 10 years since the big fight, Hiroya Munakata’s non blood-related younger brother Takashi (Shingo Tsurumi) is released…