Plot

Set in the late Edo Period. Jirokichi (Hideaki Takizawa) plays around during the day, but at night becomes a completely different person. His nickname is Nezumi-Kozo (literally "Rat Boy"). Jirokichi steals gold coins from corrupt samurai families and hands it over to the poor. He works with his younger sister Kosode (Shiori Kutsuna).—AsianWiki

Under the rule of Shogun Ienari, the samurais and the townspeople are all discontented and grumbling about their lot in life. Amidst all these, there lives a man by the name of Jirokichi, popularly known as Nezumi Kozo. Jirokichi runs a bar with the help of his sister, Kosode. Unbeknownst to everyone, Jirokichi and Kosode are always helping the victimised weak and poor from being bullied by the evil rich.