In volatile 1920s Tianjin, a mere decade after China's last imperial dynasty was overthrown, a clandestine martial arts circle arose to deter crime and maintain peace between rival martial arts schools. But after a renowned master dies and names his apprentice rather than his son as his successor, he unwittingly kicks off a fierce power struggle that will bring the entire city to the brink of chaos, as the unwritten rule of keeping peace within 100 yards of the academy walls is broken.