Xiu Xiu, a 15-year-old girl living in the city of Chengdu, moves out to study horses in the countryside with a nomadic Tibetan. She is told that after six months, she will return to take charge of her all-girl cavalry unit. However, she quickly discovers that she is not returning. She learns lessons about life while struggling against corrupt government officials who manipulate her hopes and body. Her only friend is the eunuch horseman, Lao Jin.