In a fourth-century tale, two farmers get lost in a pleasure grotto and unwittingly sever their fragile ties with the mortal world. Surprisingly, this simple cautionary fantasy spawned a complex literary tradition. The narrative instability of the tale was part of its snowballing appeal. Early in the tale's journey through literary history, the girls met by the farmers morphed into female entertainers, Daoist priestesses, and spiritual transcendents. This malleability offered a wealth of artistic possibilities. The feature of "time dilation" and its associated dangers was also to become a flexible literary instrument and a defining feature of grotto fantasy literature.