In My Home Hero, ordinary father Tetsuo Tosu never expected his daughter, Reika, to become a victim of domestic violence. Suspecting that her yakuza boyfriend, Nobuto Matori, is responsible, Tetsuo begins digging into Nobuto and the people around him. The search for evidence leads him to Reika's apartment, where he realizes that his daughter is not Nobuto's first victim and that an even worse fate may be waiting for her.
When Nobuto catches him there, Tetsuo kills him in the fight that follows. With his wife's help, he hides the body to avoid immediate retaliation from the yakuza, only to learn that Nobuto is the son of the mafia's head. As the Tosu family falls under suspicion for Nobuto's disappearance, Tetsuo and his wife are forced into a battle of wits against a ruthless criminal organization and its relentless investigation, using every bit of ingenuity they have to protect Reika.