自1958年起，占里村的人口总数几乎毫无变动。依照村规，每户人家最多只能要一儿一女两个孩子，以控制人口增长和管理资源。想生男生女，都要靠村中药师的秘方:换花草，该方法为占里侗寨所独有。该草药由村中唯一的药师管理，她将药给准备生第二胎的妇女并确保婴儿性别不同于第一胎。该影片以占里村由来已久的计划生育为背景，探究了该村的人口控制和生育观念，并对神秘的换花草和药师进行了深度发掘。
The village of ZhanLi has had almost zero change in population size since 1959. In order to maintain a stable population and successfully manage their limited resources, each family in the village vows to have a maximum of only two children, one boy and one girl. This ability to determine the sex of children is unique to this Dong village, and depends solely on a secret herb: Huanhua Cao. The secret of the herb is closely guarded by the village’s Medicine Master, who prescribes her herbal potion to expecting parents in order to ensure that the sex of their second and final child differs from that of the first. This film investigates the phenomenon of population control and fertility within the context of ZhanLi’s long history of family planning, exploring the myth of the mysterious medicine and its secretive master.