In the fictional Chinese city of Yong'an, an amateur cryptozoologist is commissioned to uncover the stories of its fabled beasts. These creatures live alongside humans in near-inconspicuousness--save their greenish skin, serrated earlobes, and strange birthmarks. Aided by her elusive former professor and his enigmatic assistant, our narrator sets off to document each beast, and is slowly drawn deeper into a mystery that threatens her very sense of self.