十九世纪初的中国，妇女还保留着裹小脚的复苏。在湖南的某个小镇，百合（李冰冰 饰）与雪花（全智贤 饰）按照当地风俗结为老同，自幼生活在一起，靠着女书交流彼此的心事，她们之间深厚的情感无 人能够取代。随着年龄的长大，百合与雪花必须嫁作人妇，从此开始了各自的苦难人生。21世纪 初，尼娜（李冰冰 饰）即将因公赴美，却在临行前夕得知好友索菲娅（全智贤 饰）车祸住院的消息。索菲娅是她自学生时代便在一起的好友，她们更按照古老的风俗结为老同。这场车祸，让久久失去联系的两人重新聚首…… 　　本片根据美籍华裔畅销作家邝丽莎所著小说《雪花与秘扇》改编。In 19th-century China, seven year old girls Snow Flower and Lily are matched as laotong - or "old sames" - bound together for eternity. Isolated by their families, they furtively communicate by taking turns writing in a secret language, nu shu, between the folds of a white silk fan. In a parallel story in present day Shanghai, the laotong's descendants, Nina and Sophia, struggle to maintain the intimacy of their own childhood friendship in the face of demanding careers, complicated love lives, and a relentlessly evolving Shanghai. Drawing on the lessons of the past, the two modern women must understand the story of their ancestral connection, hidden from them in the folds of the antique white silk fan, or risk losing one another forever.