The lead character, Mao Ran, a person of Chinese origin born and raised in Japan, has been trained in the secret martial art of her family by her drunken lecherous grandfather. Her grandfather has promised her that he'll tell her what happened to her parents to encourage her to train and fight. Without her knowledge, her grandfather signs her up to participate in a televised martial arts competition between female martial artists known as "Prime Mat". (Source: Baka-Updates)