In nineteenth century China, in a remote Hunan county, a girl named Lily, at the tender age of seven, is paired with a laotong, or "old same," in an emotional match that will last a lifetime. The two women exchange messages written on silk fans and handkerchieves using nu shu, a unique language that women created in order to communicate in secret, sharing their experiences, but when a misunderstanding arises, their friendship threatens to tear apart.