A brutal yakuza enforcer, Yamamoto, flees to Los Angeles after his clan is defeated in a violent criminal war, teaming up with his estranged half-brother Ken and forming a new gang that quickly takes control of the city's Mexican drug trade. As they expand their turf, Yamamoto becomes a formidable force, earning the respect of his peers as "Aniki," elder brother, but soon finds himself in a desperate situation after a ruthless Italian Mafia strikes back. With its blend of action, drama, and culture clash, Brother is a gritty, unapologetic portrayal of loyalty, honor, and the dark underbelly of Los Angeles' criminal underworld.